A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.

FIELD OF THE INVENTION
 This invention is directed to generally linear compounds or "strands"
 wherein naturally-occurring nucleobases or other nucleobase-binding
 moieties preferably are covalently bound to a polyamide backbone. In
 particular, the invention concerns compounds wherein two such strands
 coordinate through hydrogen bonds to form a DNA-like double strand.
 BACKGROUND OF THE INVENTION
 The transcription and processing of genomic duplex DNA is controlled by
 generally proteinaceous transcription factors that recognize and bind to
 specific DNA sequences. One strategy for the control of gene expression is
 to add to a cell double-stranded DNA or double-stranded DNA-like
 structures that will bind to the desired factor in preference to or in
 competition with genomic DNA, thereby inhibiting processing of the DNA
 into a protein. This modulates the protein's action within the cell and
 can lead to beneficial effects on cellular function. Naturally occurring
 or unmodified oligonucleotides are unpractical for such use because they
 have short in vivo half-lives and they are poor cell membrane penetrators.
 These problems have resulted in an extensive search for improvements and
 alternatives. In order to improve half-life as well as membrane
 penetration, a large number of variations in polynucleotide backbones has
 been undertaken. These variations include the use of methylphosphonates,
 phosphorothioates, phosphordithioates, phosphoramidates, phosphate esters,
 bridged phosphoroamidates, bridged phosphorothioates, bridged
 methylenephosphonates, dephospho internucleotide analogs with siloxane
 bridges, carbonate bridges, carboxymethyl ester bridges, acetamide
 bridges, carbamate bridges, thioether, sulfoxy, sulfono bridges, various
 "plastic" DNAs, .alpha.-anomeric bridges, and borane derivatives. The
 great majority of these backbone modifications lead to decreased stability
 for hybrids formed between the modified oligonucleotide and its
 complementary native oligonucleotide, as assayed by measuring T.sub.m
 values.
 Consequently, there remains a need in the art for stable compounds that can
 form double-stranded, helical structures mimicking double-stranded DNA.
 OBJECTS OF THE INVENTION
 It is one object of the present invention to provide compounds that mimic
 the double-helical structure of DNA.
 It is a further object of the invention to provide compounds wherein
 linear, polymeric strands coordinate through hydrogen bonds to form double
 helices.
 It is another object to provide compounds wherein naturally-occurring
 nucleobases or other nucleobase-binding moieties are covalently bound to a
 non-sugar-phosphate backbone.
 It is yet another object to provide therapeutic, diagnostic, and
 prophylactic methods that employ such compounds.
 SUMMARY OF THE INVENTION
 The present invention provides a novel class of compounds, known as peptide
 nucleic acids (PNAs), that can coordinate with one another or with
 single-stranded DNA to form double-stranded (i.e., duplex) structures. The
 compounds include homopolymeric PNA strands and heteropolymeric PNA
 strands (e.g., DNA/PNA strands), which coordinate through hydrogen bonding
 to form helical structures. Duplex structures can be formed, for example,
 between two complementary PNA or PNA/DNA strands or between two
 complementary regions within a single such strand.
 In certain embodiments, each strand of the double-stranded compounds of the
 invention includes a sequence of ligands covalently bound by linking
 moieties and at least one of said linking moieties comprising an amide,
 thioamide, sulfinamide or sulfonamide linkage. The ligands on one strand
 hydrogen bond with ligands on the other strand and, together, assume a
 double helical structure. The compounds of the invention preferably
 comprise ligands linked to a polyamide backbone. Representative ligands
 include either the four main naturally occurring DNA bases (i.e., thymine,
 cytosine, adenine or guanine) or other naturally occurring nucleobases
 (e.g., inosine, uracil, 5-methylcytosine or thiouracil) or artificial
 bases (e.g., bromothymine, azaadenines or azaguanines, 5-propynylthymine,
 etc.) attached to a peptide backbone through a suitable linker. These
 ligands are linked to the polyamide backbone through aza nitrogen atoms or
 through amido and/or ureido tethers.
 In certain preferred embodiments, the peptide nucleic acids of the
 invention have the general formula (I):
 ##STR1##
 wherein:
 n is at least 2,
 each of L.sup.1 -L.sup.n is independently selected from the group
 consisting of hydrogen, hydroxy, (C.sub.1 -C.sub.4)alkanoyl, naturally
 occurring nucleobases, non-naturally occurring nucleobases, aromatic
 moieties, DNA intercalators, nucleobase-binding groups, heterocyclic
 moieties, and reporter ligands, at least one of L.sup.1 -L.sup.n being a
 naturally occurring nucleobase, a non-naturally occurring nucleobase, a
 DNA intercalator, or a nucleobase-binding group;
 each of C.sup.1 -C.sup.n is (CR.sup.6 R.sup.7).sub.y where R.sup.6 is
 hydrogen and R.sup.7 is selected from the group consisting of the side
 chains of naturally occurring alpha amino acids, or R.sup.6 and R.sup.7
 are independently selected from the group consisting of hydrogen, (C.sub.2
 -C.sub.6)alkyl, aryl, aralkyl, heteroaryl, hydroxy, (C.sub.1
 -C.sub.6)alkoxy, (C.sub.l -C.sub.6)alkylthio, NR.sup.3 R.sup.4 and
 SR.sup.5, where R.sup.3 and R.sup.4 are as defined above, and R.sup.5 is
 hydrogen, (C.sub.1 -C.sub.6)alkyl, hydroxy-, alkoxy-, or
 alkylthio-substituted (C.sub.1 -C.sub.6)alkyl, or R.sup.6 and R.sup.7
 taken together complete an alicyclic or heterocyclic system;
 each of D.sup.1 -D.sup.n is (CR.sup.6 R.sup.7).sub.z where R.sup.6 and
 R.sup.7 are as defined above;
 each of y and z is zero or an integer from 1 to 10, the sum y+z being
 greater than 2 but not more than 10;
 each of G.sup.1 -G.sup.n-1 is --NR.sup.3 CO--, --NR.sup.3 CS--, --NR.sup.3
 SO-- or --NR.sup.3 SO.sub.2 --, in either orientation, where R.sup.3 is as
 defined above;
 each pair of A.sup.1 -A.sup.n and B.sup.1 -B.sup.n are selected such that:
 (a) A is a group of formula (IIa), (IIb) or (IIc) and B is N or R.sup.3
 N.sup.+ ; or
 (b) A is a group of formula (IId) and B is CH;
 ##STR2##
 where:
 X is O, S, Se, NR.sup.3, CH.sub.2 or C(CH.sub.3).sub.2 ;
 Y is a single bond, O, S or NR.sup.4 ;
 each of p and q is zero or an integer from 1 to 5, the sum p+q being not
 more than 10;
 each of r and s is zero or an integer from 1 to 5, the sum r+s being not
 more than 10;
 each R.sup.1 and R.sup.2 is independently selected from the group
 consisting of hydrogen, (C.sub.1 -C.sub.4)alkyl which may be hydroxy- or
 alkoxy- or alkylthio-substituted, hydroxy, alkoxy, alkylthio, amino and
 halogen;
 each of G.sup.1 -G.sup.n-1 is --NR.sup.3 CO--, --NR.sup.3 CS--, --NR.sup.3
 SO-- or --NR.sup.3 SO.sub.2 --, in either orientation, where R.sup.3 is as
 defined above;
 Q is --CO.sub.2 H, --CONR'R", --SO.sub.3 H or --SO.sub.2 NR'R" or an
 activated derivative of --CO.sub.2 H or --SO.sub.3 H; and
 I is --NHR'"R"" or --NR'"C(O)R"", where R', R", R'" and R"" are
 independently selected from the group consisting of hydrogen, alkyl, amino
 protecting groups, reporter ligands, intercalators, chelators, peptides,
 proteins, carbohydrates, lipids, steroids, nucleosides, nucleotides,
 nucleotide diphosphates, nucleotide triphosphates, oligonucleotides,
 oligonucleosides and soluble and non-soluble polymers.
 In certain embodiments, at least one A is a group of formula (IIc) and B is
 N or R.sup.3 N.sup.+. In other embodiments, A is a group of formula (IIa)
 or (IIb), B is N or R.sup.3 N.sup.+, and at least one of y or z is not 1
 or 2.
 Preferred peptide nucleic acids have general formula (IIIa)-(IIIc):
 ##STR3##
 wherein:
 each L is independently selected from the group consisting of hydrogen,
 phenyl, heterocyclic moieties, naturally occurring nucleobases, and
 non-naturally occurring nucleobases;
 each R.sup.7' is independently selected from the group consisting of
 hydrogen and the side chains of naturally occurring alpha amino acids;
 n is an integer from 1 to 60;
 each of k, l, and m is independently zero or an integer from 1 to 5;
 p is zero or 1;
 R.sup.h is OH, NH.sub.2 or --NHLysNH.sub.2 ; and
 R.sup.i is H or COCH.sub.3.
 Particularly preferred are compounds having formula (IIIa)-(IIIc) wherein
 each L is independently selected from the group consisting of the
 nucleobases thymine (T), adenine (A), cytosine (C), guanine (G) and uracil
 (U), k and m are zero or 1, and n is an integer from 1 to 30, in
 particular from 4 to 20.
 The peptide nucleic acids of the invention are synthesized by adaptation of
 standard peptide synthesis procedures, either in solution or on a solid
 phase. The synthons used are monomer amino acids or their activated
 derivatives, protected by standard protecting groups. The PNAs also can be
 synthesized by using the corresponding diacids and diamines.
 Thus, the novel monomer synthons according to the invention are selected
 from the group consisting of amino acids, diacids and diamines having
 general formulae:
 ##STR4##
 wherein L, A, B, C and D are as defined above, except that any amino groups
 therein may be protected by amino protecting groups; E is COOH, CSOH,
 SOOH, SO.sub.2 OH or an activated derivative thereof; and F is NHR.sup.3
 or NPgR.sup.3, where R.sup.3 is as defined above and Pg is an amino
 protecting group.
 Preferred monomer synthons according to the invention have formula
 (VIIIa)-(VIIIc):
 ##STR5##
 or amino-protected and/or acid terminal activated derivatives thereof,
 wherein L is selected from the group consisting of hydrogen, phenyl,
 heterocyclic moieties, naturally occurring nucleobases, and non-naturally
 occurring nucleobases; and R.sup.7' is selected from the group consisting
 of hydrogen and the side chains of naturally occurring alpha amino acids.
 These compounds are able to recognize one another to produce double
 helices. Such recognition can span sequences 5-60 base pairs long.
 Sequences between 10 and 20 bases are of interest since this is the range
 within which unique DNA sequences of prokaryotes and eukaryotes are found.
 Sequences between 17-18 bases are of particular interest since this is the
 length of unique sequences in the human genome.
 Thus, in one aspect, the present invention provides methods for modulating
 the activity of a transcription factor in a cell, comprising the steps of
 forming a PNA-containing double strand that binds the transcription factor
 and introducing the double strand into the cell.
 Further, the invention provides methods for modulating the activity of a
 protein in a cell, comprising the steps of forming a PNA-containing double
 strand that binds to or suppresses expression of the protein and
 introducing the double strand into the cell.
 The PNA duplex structures of the invention mimic dsDNA and can be used in
 diagnostics, therapeutics and as research reagents and kits. They can be
 used in pharmaceutical compositions by including a suitable
 pharmaceutically acceptable diluent or carrier.

DETAILED DESCRIPTION OF THE INVENTION
 As will be recognized, a variety of double-stranded (i.e., duplex)
 PNA-containing structures can be prepared according to the present
 invention. Representative duplexes can be formed within a single
 homopolymeric PNA strand or a single heteropolymeric strand (e.g., a
 chimera PNA-DNA or PNA-RNA strand), or between two homopolymeric PNA
 strands, two heteropolymeric PNA strands, or a homopolymeric PNA strand
 and a heteropolymeric PNA strand.
 Each PNA strand or PNA portion of a chimera strand preferably comprises a
 plurality of ligands, L, linked to a backbone via attachment at the
 position found in nature, i.e., position 9 for adenine or guanine, and
 position 1 for thymine or cytosine. Alternatively, L can be a
 non-naturally occurring nucleobase (nucleobase analog), another
 base-binding moiety, an aromatic moiety, (C.sub.1 -C.sub.4)alkanoyl,
 hydroxy or even hydrogen. It will be understood that the term nucleobase
 includes nucleobases bearing removable protecting groups. Some typical
 nucleobase ligands and illustrative synthetic ligands are shown in FIG. 2
 of WO 92/20702. Furthermore, L can be a DNA intercalator, a reporter
 ligand such as, for example, a fluorophor, radio label, spin label,
 hapten, or a protein-recognizing ligand such as biotin. In monomer
 synthons, L can be blocked with protecting groups, as illustrated in FIG.
 4 of WO 92/20702.
 Linker A can be a wide variety of groups such as --CR.sup.1 R.sup.2 CO--,
 --CR.sup.1 R.sup.2 CS--, --CR.sup.1 R.sup.2 CSe--, --CR.sup.1 R.sup.2
 CNHR.sup.2 --, --CR.sup.1 R.sup.2 C.dbd.CH.sub.2 -- and --CR.sup.1 R.sup.2
 C.dbd.C(CH.sub.3).sub.2 --, where R.sup.1, R.sup.2 and R.sup.3 are as
 defined above. Preferably, A is methylenecarbonyl (--CH.sub.2 CO--), amido
 (--CONR.sup.3 --), or ureido (--NR.sup.3 CONR.sup.3 --). Also, A can be a
 longer chain moiety such as propanoyl, butanoyl or pentanoyl, or
 corresponding derivative, wherein O is replaced by another value of X or
 the chain is substituted with R.sup.1 R.sup.2 or is heterogenous,
 containing Y. Further, A can be a (C.sub.2 -C.sub.6)alkylene chain, a
 (C.sub.2 -C.sub.6)alkylene chain substituted with R.sup.1 R.sup.2 or can
 be heterogenous, containing Y. In certain cases, A can just be a single
 bond.
 In one preferred form of the invention, B is a nitrogen atom, thereby
 presenting the possibility of an achiral backbone. B can also be R.sup.3
 N.sup.+, where R.sup.3 is as defined above, or CH.
 In the preferred form of the invention, C is --CR.sup.6 R.sup.7 --, but can
 also be a two carbon unit, i.e. --CHR.sup.6 CHR.sup.7 -- or --CR.sup.6
 R.sup.7 CH.sub.2 --, where R.sup.6 and R.sup.7 are as defined above.
 R.sup.6 and R.sup.7 also can be a heteroaryl group such as, for example,
 pyrrolyl, furyl, thienyl, imidazolyl, pyridyl, pyrimidinyl, indolyl, or
 can be taken together to complete an alicyclic system such as, for
 example, 1,2-cyclobutanediyl, 1,2-cyclopentanediyl or 1,2-cyclohexanediyl.
 In a preferred form of the invention, E in the monomer synthon is COOH or
 an activated derivative thereof, and G in the oligomer is --CONR.sup.3 --.
 As defined above, E also can be CSOH, SOOH, SO.sub.2 OH or an activated
 derivative thereof, whereby G in the oligomer becomes --CSNR.sup.3 --,
 --SONR.sup.2 -- and --SO.sub.2 NR.sup.3 --, respectively. The activation
 can, for example, be achieved using an acid anhydride or an active ester
 derivative, wherein hydrogen in the groups represented by E is replaced by
 a leaving group suited for generating the growing backbone.
 The amino acids which form the backbone can be identical or different. We
 have found that those based on 2-aminoethylglycine are especially well
 suited to the purpose of the invention.
 In some cases it may be of interest to attach ligands at either terminus
 (Q, I) to modulate other properties of the PNAs. Representative ligands
 include DNA intercalators or basic groups, such as lysine or polylysine.
 Further groups such as carboxy and sulfo groups could also be used. The
 design of the synthons further allows such other moieties to be located on
 non-terminal positions.
 Duplexes according to the present invention can be assayed for their
 specific binding activity to a transcription factor. As used herein, the
 term "binding affinity" refers to the ability of a duplex to bind to a
 transcription factor via hydrogen bonds, van der Waals interactions,
 hydrophobic interactions, or otherwise. For example a duplex can bind to a
 "leucine zipper" transcription factor or a helix-loop-helix transcription
 factor via positively charged amino acids in one region of the
 transcription factor.
 Transcription factors, as the term is used herein, are DNA- or RNA-binding
 proteins that regulate the expression of genes. HIV tat and c-rel are
 examples of transcription factors which regulate the expression of genes.
 Also encompassed by the term are DNA and RNA binding proteins which are
 not strictly considered transcription factors, but which are known to be
 involved in cell proliferation. These transcription factors include c-myc,
 fos, and jun. Methods of the present invention are particularly suitable
 for use with transcription factor as target molecules since transcription
 factors generally occur in very small cellular quantities.
 The compounds of the present invention also may be useful to bind to other
 target molecules. Target molecules of the present invention can include
 any of a variety of biologically significant molecules. Such other target
 molecules can be nucleic acid strands such as significant regions of DNA
 or RNA. Target molecules also can be carbohydrates, glycoproteins or other
 proteins. In some preferred embodiments of the present invention, the
 target molecule is a protein such as an immunoglobulin, receptor, receptor
 binding ligand, antigen or enzyme and more specifically can be a
 phospholipase, tumor necrosis factor, endotoxin, interleukin, plasminogen
 activator, protein kinase, cell adhesion molecule, lipoxygenase, hydrolase
 or transacylase. In other embodiments of the invention the target
 molecules can be important regions of the human immunodeficiency virus,
 Candida, herpes viruses, papillomaviruses, cytomegalovirus, rhinoviruses,
 hepatitises, or influenza viruses. In yet other embodiments of the present
 invention the target molecules can be regions of an oncogene. In still
 further embodiments, the target molecule is ras 47-mer stem loop RNA, the
 TAR element of human immunodeficiency virus or the gag-pol stem loop of
 human immunodeficiency virus (HIV). Still other targets can induce
 cellular activity. For example, a target can induce interferon.
 In binding to transcription factors or other target molecules, the
 transcription factor or other target molecule need not be purified. It can
 be present, for example, in a whole cell, in a humoral fluid, in a crude
 cell lysate, in serum or in other humoral or cellular extract. Of course,
 purified transcription factor or a purified form of an other target
 molecule is also useful in some aspects of the invention.
 In still other embodiments of the present invention, synthetically prepared
 transcription factor or other target molecule can be useful. A
 transcription factor or other target molecule also can be modified, such
 as by biotinylation or radiolabeling. For example, synthetically prepared
 transcription factor can incorporate one or more biotin molecules during
 synthesis or can be modified post-synthesis.
 An illustrative series of PNA oligomers according to the invention can be
 prepared as described in Example 1 below and have been designed as
 follows:
 (1) Formulas 1 (SEQ ID NO:1) and 2 (SEQ ID NO:2), two complementary
 antiparallel PNA decamers that are not self-complementary:
 (aminoterminal) H-Gly-GTAGATCACT-LysNH.sub.2 1
EQU NH.sub.2 Lys-CATCTAGTGA-GlyH (aminoterminal) 2
 (2) Formula 3 (SEQ ID NO:3), a single PNA oligomer possessing a
 self-complementary motif ten base pairs long with an intervening loop
 region containing five base units:

##STR6##
 (3) Formula 4 (SEQ ID NO:4), a single PNA oligomer possessing a self
 complementary motif of ten base pairs long linked by an oligomethylene
 (n=1-10) spacer:
 ##STR7##
 (4) Formula 5 (SEQ ID NO:5), a single PNA oligomer possessing a
 self-complementary motif ten base pairs long on one side interrupted by a
 three base bulge and an intervening loop region containing five base
 units:
 ##STR8##
 In each of the foregoing, NH.sub.2 Lys is intended to indicate that a
 lysine-amide is attached to the carboxyl end of the PNA. Use of such
 lysine-amide is not necessary; however, its use is preferred since it is
 believed to suppress aggregation of the oligomers. The aminoterminal end
 of the PNA is substituted with a glycine residue to avoid migration of the
 N-terminal nucleobase. The PNA amino-terminal and carboxy-terminal ends
 are intended to correspond, respectively, to the 5'-ends and 3'-ends of
 DNA. As a consequence of the designed sequences, these PNAs form duplexes
 having DNA-like antiparallel orientations. These PNAs additionally are
 capable of adopting a tertiary structure.
 As can be seen in FIG. 1, the circular dichroism (CD) of PNA 10-mers of
 Example 1 are almost vanishingly small, indicating that there is no
 preferred helical stacking of bases. However, a strong CD spectrum arises
 upon titration of one 10-mer with the complementary 10-mer, a saturation
 obtained at about 1:1 stoichiometry, as shown in FIG. 2. The CD spectrum
 resembles that of B-DNA, indicating a right-handed helix. It is believed
 that a PNA-PNA complex having no preferred helicity initially is formed.
 The kinetics by which this double-stranded structure reorganizes into a
 uniform, right-handed double helix has been monitored and the activation
 parameters for the process determined.
 For DNA, circular dichroism in the nucleobase absorption region arises both
 from helical stacking of the bases, by excitation interactions between the
 neighboring bases, and from interactions with transitions of the chiral
 riboses moieties. In contrast, in PNA the electronic interaction between
 most of the bases and the chiral terminal lysine is negligible and the
 main source of circular dichroism is attributable almost solely to the
 chiral orientation of the base-pairs relative to each other. The
 right-handed helicity observed for PNA is determined by the chiral bias of
 a terminal lysine residue. The formation of a helical duplex between the
 two complementary PNA oligomers was slow enough to be followed by the
 increase in circular dichroism with time. This is in contrast with DNA-DNA
 duplex formation, which occurs within seconds. The development of circular
 dichroism follows first order reaction kinetics. Activation parameters
 have been determined by following the association at various temperatures,
 as shown in FIG. 3. Control experiments with different PNA concentrations
 gave identical results, confirming that the PNA-PNA association is fast
 and includes a reorganization process in an already base-paired complex.
 This observation is further supported by the absence of time dependent
 hypochromicity in normal absorption spectra. Such a reorganization in the
 corresponding cases of DNA-DNA and DNA-PNA decamers duplexes is too fast
 to be observed, indicating that the local chirality of the ribose in those
 cases immediately determines the handedness of base stacking. The
 conclusion is that the association of the two PNA-oligomers is fast in the
 base-pairing first step, but is followed by a slow seeding of the duplex
 chirality, from the terminal lysine residue, towards its right-handed
 helical structure. The activation energy obtained is 33.9 kJ/mole, which
 is low because the transition state is associated with a large negative
 entropy change (.DELTA.S=-173 kJ/mole; see, e.g., FIG. 3), implying a
 highly ordered transition state. This is a strong indication that the
 rate-limiting inversion step is a cooperative seeding of chirality from
 the terminal base-pairs involving the entire stack of bases.
 We believe this is the first time a pure cooperative inversion transition
 in a nucleic acid-like structure has been isolated. Also, in contrast to
 DNA wherein ribose residues act as local chiral centers, optical activity
 of PNA-PNA duplexes is entirely a result of the helical arrangement of the
 nucleobases relative to each other. The CD spectrum can be compared with
 the theoretical and experimental spectra that have been generated for
 helix stacks of DNA bases to demonstrate the mimicry of DNA duplex
 structure. These PNA-PNA duplexes therefore are useful mimics of DNA for
 the purpose of modulating the expression or transcription of DNA and thus
 modulating a disease state to the benefit of a living organism.
 The utility of these PNA-containing duplex structures can be illustrated by
 constructing PNA sequences which correspond to various sequences of the
 HIV TAR element that have the potential to form duplex structures either
 as stem-loop structures or two PNAs forming a duplex structure. In a
 competition assay, PNA structures that bind the tat transcription factor
 prevent binding of the competitor TAR sequence present in the incubation
 mixture. As the TAR RNA sequence is biotinylated only tat proteins
 available to bind to TAR will remain on the microtiter plate after washing
 away unbound molecules and tat protein complexed to a PNA sequence. The
 concentration dependence of the competition between the TAR PNA structures
 and biotinylated TAR structure will serve to define those sequences
 capable of effectively competing for tat and thus useful as HIV modulatory
 agents.
 Additional objects, advantages, and novel features of this invention will
 become apparent to those skilled in the art upon examination of the
 following examples thereof, which are not intended to be limiting.
 EXAMPLE 1
 Synthesis of PNA Structures
 PNA having formulas 1 through 5 above are prepared generally according to
 the synthetic protocols described generally in Examples A, B and C and
 more particularly in Examples 11-127. Migration of the last nucleobase
 methylcarbonyl moiety to the terminal nitrogen is prevented by capping the
 N-terminus of the PNA chain with a glycine residue. The compounds are
 purified by HPLC (reverse phase, 0.1% trifluoroacetic acid in
 acetonitrile/water) and the composition verified by mass spectrometry.
 EXAMPLE 2
 Binding and Helix Formation of Complementary Antiparallel PNA Strands (FIG.
 1)
 The circular dichroism spectra of PNA-PNA mixtures were obtained by
 titrating PNA having sequence H-GTAGATCACT-LysNH2 (PNA formula 1 SEQ ID
 NO: 1) with PNA having sequence H-AGTGATCTAC-LysNH2 (PNA formula 2 SEQ ID
 NO: 2). The concentration of PNA formula 1 was held constant (50
 .mu.mole/L) and the concentration of PNA formula 2 was increased to
 provide the following formula 2:formula 1 stoichiometries: 0.25 (Curve C),
 0.50 (Curve D), 0.75 (Curve E), 1.00 (Curve F), and 1.25 (Curve G). The
 hybridizations were performed in a 5 mmol/L sodium phosphate buffer, pH
 7.0, at 20.degree. C., after 20 minutes of incubation. The path length was
 1 cm. Saturation was obtained at equimolar amounts of the two decamers.
 FIG. 2 shows development of negative circular dichroism (at 220 nm) as a
 function of time after mixing equimolar amounts of PNA formula 1 with PNA
 formula 2. From top to bottom, the curves correspond to the following
 temperatures: 5.degree. C., 15.degree. C., 23.degree. C., 32.degree. C.,
 41.degree. C., and 47.degree. C.
 FIG. 3 shows an Arrhenius plot of rates from the CD kinetics. The plot
 provides the activation energy as .DELTA.H=33.9 kJ/mole (with the
 approximation that (k.sub.B T/h)exp(.DELTA.S.sup..dagger-dbl. /R) is
 constant). The full rate equation is k=(k.sub.B
 T/h)exp(-.DELTA.H.sup..dagger-dbl.)exp-(.DELTA.S.sup..dagger-dbl. /R) then
 gives .DELTA.S.sup..dagger-dbl. =-173 J/mole.
 EXAMPLE 3
 PNA Having Binding Affinity for The HIV-tat Protein as Measured in a
 Competitive Inhibition Assay
 Samples of PNAs corresponding to various TAR sequences prepared by the
 method of Example 1 are incubated with recombinant tat transcription
 factor (100 .mu.M) for 15 minutes at room temperature at 1, 3, 10 ,30, and
 100 .mu.M (see, e.g., Cullen, et al., Cell 1990, 63, 655.). A competitor,
 a truncated version of the TAR sequence corresponding to residues 16-45 as
 a 2'-O-methyl oligonucleotide, is employed as a TAR sequence and is
 biotinylated at the 3'-O end by procedures generally in accordance with
 the protocols of application Ser. No. 08/032,852, Combinatorial Oligomer
 Immunoabsorbant Screening Assay For Transcription Factors And Other
 Biomolecule Binding, filed Mar. 16, 1993, the entire contents of which are
 incorporated herein by reference. This TAR sequence is added at 100 nM
 concentration. The reaction is incubated for 20 minutes and then added to
 streptavidin-coated microtiter plate wells. After unbound molecules are
 washed away with phosphate-buffered saline (PBS), 100 .mu.L of 1:500 tat
 antisera is added to each well and incubated for 2 hours. Protein A/G
 antisera phosphatase is bound to the tat antibodies and PNPP
 (p-nitrophenylphosphate) substrate (200 .mu.l) then is added. Color
 development is measured 2 hours later by reading absorbance at 405 nM on a
 Titertek Multiscan ELISA plate reader.
 EXAMPLE 4
 PNA Having Binding Affinity for the C-myc Protein
 Myc-c is a nuclear protein involved in cell proliferation, differentiation,
 and neoplastic disease and binds DNA in a sequence specific manner. See,
 e.g., Nissen, Cancer Research 1986, 46, 6217 and Blackwell, Science 1990,
 250, 1149. Crude nuclear extracts of myc-c are prepared generally in
 accordance with Franza, et al., Nature 1987, 330, 391, from HL 60 cells
 stimulated to induce the expression of myc-c.
 Phosphorothioate oligonucleotides having the sequences GAT CCC CCC ACC ACG
 TGG TGC CTG A-B (SEQ ID NO:6) and GAT CTC AGG CAC CAC GTG GTG GGG G-B (SEQ
 ID NO:7), where B=biotin, are synthesized on an automated DNA synthesizer
 (Applied Biosystems model 380B) using modified standard phosphoramidite
 chemistry with oxidation by a 0.2M solution of 3H-1,2-benzodithiole-3-one
 1,1-dioxide in acetonitrile for stepwise thiation of phosphite linkages.
 The thiation cycle wait step is 68 seconds and is followed by the capping
 step. .beta.-Cyanoethyldiisopropyl phosphoramidites can be purchased from
 Applied Biosystems (Foster City, Calif.). Bases are deprotected by
 incubation in methanolic ammonia overnight. Following base deprotection,
 the oligonucleotides are dried in vacuo. Removal of 2'-hydroxyl
 t-butyldimethylsilyl protecting groups is effected by incubating the
 oligonucleotide in 1M tetrabutylammonium fluoride in tetrahydrofuran
 overnight. The RNA oligonucleotides are further purified on C.sub.18
 Sep-Pak cartridges (Waters, Division of Millipore Corp., Milford, Mass.)
 and ethanol precipitated. The phosphorothioate oligonucleotides are
 hybridized to create the double stranded NF-kB binding site.
 A series of PNA-PNA duplexes is synthesized and hybridized to give a new
 series of PNA duplexes corresponding to different length portions of the
 myc-c binding sequence. Each duplex is incubated in triplicate at
 concentrations of 1, 3, 10, 30, and 100 .mu.M with the HL-60 extract
 described above. The myc P=S binding site then is added and the mixtures
 are incubated and washed with PBS. An antibody directed to the leucine
 zipper region of the myc protein (Santa Cruz Biotechnology) is added at a
 1:1000 dilution. Non-bound molecules are washed away with PBS. Binding of
 myc to biotinylated c-myc transcription factor is quantitated by adding
 100 .mu.l of 1:500 tat antisera to each well for 2 hours. Protein
 A/G-alkaline phosphatase (Pierce; 1:5000; 100 .mu.l) then is added and any
 excess is removed by washing with PBS. PNPP substrate (200 .mu.l) then is
 added. Color development is measured 2 hours later by reading absorbance
 at 405 nM on a Titertek Multiscan ELISA plate reader.
 EXAMPLE 5
 PNA Having Binding Affinity for the C-rel Transcription Factor
 C-rel has been shown to represent a constituent of the NF-kB site binding
 transcription factor, which plays a crucial role in the expression of a
 number of genes including the immunoglobulin k light chain gene, IL-2ra,
 and MHC. (see, e.g., Gilmore, et al., Cell 1986, 62, 791.)
 Crude nuclear extracts are prepared as detailed by Franza, et al., Nature
 1987, 330, 391, from Jurkat cells stimulated 4 hours with 1 .mu.M PHA and
 100 nM PMA to induce the expression of rel. The extract is then
 preabsorbed with 100 .mu.l streptavidin agarose per ml for 10 minutes.
 This is followed with the addition of poly dI.dC as a nonspecific
 competitor at a concentration of 100 .mu.g/ml of extract. Nuclear extracts
 containing the biotinylated NF-kB binding site competitor are prepared as
 in Example 4, above.
 A series of PNA duplexes is synthesized to correspond to various length
 fragments of the consensus binding sequence of c-rel. NF-kB binding site
 competitor is added to each duplex and the resulting samples are washed.
 Antibody directed to rel is added. The amount of rel bound is quantitated
 by adding 100 .mu.l of 1:500 rel antisera to each well for 2 hours.
 Protein A/G-alkaline phosphatase (Pierce; 1:5000; 100 .mu.l) the is added
 and any excess is removed by washing with PBS. PNPP substrate (200 .mu.l)
 then is added. Color development is measured 2 hours later by reading
 absorbance at 405 nM on a Titertek Multiscan ELISA plate reader.
 EXAMPLE 6
 PNA Having Binding Affinity for the AP-1 Transcription Factor
 Genes belonging to the fos and jun oncogene families encode nuclear
 proteins associated with a number of transcriptional complexes, see, e.g.,
 Konig, et al., EMBO Journal 1989, 8, 2559. C-jun is a major component of
 the AP-1 binding site, which was originally shown to regulate tissue
 plasminogen activator (TPA) induced expression of responsive genes through
 the TPA response element (TRE). The jun protein forms homo- or
 heterodimers which bind the TRE. The fos protein is only active as a
 heterodimer with any of the jun family of proteins. Fos/jun heterodimers
 have a much higher affinity for the TRE than jun homodimers.
 Both the fos and the jun cDNA have been cloned downstream of the Sp6
 promoter. RNA is produced from each plasmid in vitro, then used to produce
 functional jun and fos proteins in rabbit reticulocyte lystates. The fos
 and jun proteins are then allowed to bind to the biotinylated AP-1 binding
 site in competition with PNA duplex sequences constructed as mimics of the
 proper consensus sequence for binding fos and jun, CGC TTG GTG ACT CAG CCG
 GAA (SEQ ID NO: 8). Binding is quantitated with an antibody directed to
 fos or jun. When the fos alone is incubated with the AP-1 site there will
 be no detectable binding with either antibody. When the jun alone is
 incubated with the binding site, a signal will be detected with only the
 jun antibody. This is consistent with the formation of a jun homodimer,
 which has previously been demonstrated to bind AP-1. When the fos and jun
 proteins are mixed a signal will be detected with both fos and jun
 antibodies. This is consistent with the formation of a fos/jun homodimer
 which is known to bind the AP-1 site and should be detectable with either
 antibody.
 PNA sequences of the present invention can be tested for the ability to
 block the formation of the fos/jun heterodimer. Molecules which block
 formation will decrease the signal detected with the fos antibody, but not
 the jun antibody.
 EXAMPLE 7
 Chimera Macromolecule Having Peptide Nucleic Acids Section Attaching to 3'
 Terminus of a 2'-Deoxy Phosphorothioate Oligonucleotide Section
 A first section of peptide nucleic acids is prepared as per PCT patent
 application WO 92/20702. The peptide nucleic acids are prepared from the C
 terminus towards the N terminus using monomers having protected amino
 groups. Following completion of the peptide region, the terminal amine
 blocking group is removed and the resulting amine reacted with a
 3'-C-(formyl)-2', 3'-dideoxy-5'-trityl nucleotide as prepared per the
 procedure of Vasseur, et. al., J. Am. Chem. Soc. 1992, 114, 4006. The
 condensation of the amine with the aldehyde moiety of the C-formyl
 nucleoside is effected as per the conditions of the Vasseur, ibid., to
 yield an intermediate imine linkage. The imine linkage is reduced under
 reductive the alkylation conditions of Vasseur, ibid., with
 HCHO/NaBH.sub.3 CN/AcOH to yield the nucleoside connected to the peptide
 nucleic acid via an methyl alkylated amine linkage. An internal 2'-deoxy
 phosphorothioate nucleotide region is then continued from this nucleoside
 as per standard automatated DNA synthetic protocols (see Oligonucleotide
 synthesis, a practic approach, M. J. Gait ed, IRL Press, 1984).
 EXAMPLE 8
 Chimera Macromolecule Having Peptide Nucleic Acids Section Attaching to 5'
 Terminus of a Phosphorothioate Oligonucleotide Section
 A phosphorothioate oligonucleotide is prepared in the standard manner on a
 solid support as per standard protocols (see Oligonucleotides and
 Analogues, A Practical Approach, F. Eckstein Ed., IRL Press, 1991. The
 dimethoxytrityl blocking group on that nucleotide is removed in the
 standard manner. Peptide synthesis for the peptide region is commenced by
 reaction of the carboxyl end of the first peptide nucleic acid of this
 region with the 5' hydroxy of the last nucleotide of the DNA region.
 Coupling is effected via EDC (Pierce) in pyridine to form an ester linkage
 between the peptide and the nucleoside. Peptide synthesis is then
 continued in the manner of patent application WO 92/20702 to complete the
 peptide nucleic acid region.
 EXAMPLE 9
 Double Stranded Structures that Include Chimera Strand
 Duplex structures will be formed with the chimera strands of Examples 7 and
 8. Duplex structures can include duplexes between a PNA-RNA or PNA-DNA
 strand and a RNA strand, a PNA-RNA or PNA-DNA strand and a DNA strand, a
 PNA-RNA or PNA-DNA strand and a PNA strand or a PNA-RNA or PNA-DNA strand
 and a further chimeric PNA-DNA or PNA-RNA strand.
 EXAMPLE 10
 Binding Between PNA Containing Double Stranded Structure and Transcription
 Factor or Other Protein
 A double stranded PNA structure, a structure containing PNA chimeric strand
 and a nucleic acid strand or two PNA chimera strands will be used to bind
 to or otherwise modulate single stranded DNA, double stranded DNA, RNA, a
 transcription factor or other protein. In the use of a PNA containing
 chimera, part of the binding between the chimera and the transcription
 factor or other protein can include binding between the sugar-phosphate
 backbone of the DNA or RNA portion of the chimera and hydrogen bonding
 between the ligands, e.g. nucleobases, of the PNA portion of the chimera.
 Binding to the sugar-phosphate backbone includes binding to phosphodiester
 linkages, phosphorothioate linkages or other linkgages that may be used as
 the backbone of the DNA or RNA. In other instances, bonding can include
 hydrophobic contacts between hydrophobic groups on the ligands, including
 nucleobases, of the PNA or the nucleobases of the nucleic acid portion of
 the chimera with like hydrophobic groups on proteins that are being bound.
 Such hydrophobic groups on the chimeric strand include the methyl groups
 on thymine nucleobases.
 Those skilled in the art will appreciate that numerous changes and
 modifications can be made to the preferred embodiments of the invention
 and that such changes and modifications can be made without departing from
 the spirit of the invention. It is therefore intended that the appended
 claims cover all such equivalent variations as fall within the true spirit
 and scope of the invention.
 EXAMPLE A
 Synthesis of PNA Oligomers and Polymers
 The principle of anchoring molecules onto a solid matrix, which helps in
 accounting for intermediate products during chemical transformations, is
 known as Solid-Phase Synthesis or Merrifield Synthesis (see, e.g.,
 Merrifield, J. Am. Chem. Soc., 1963, 85, 2149 and Science, 1986, 232,
 341). Established methods for the stepwise or fragmentwise solid-phase
 assembly of amino acids into peptides normally employ a beaded matrix of
 slightly cross-linked styrene-divinylbenzene copolymer, the cross-linked
 copolymer having been formed by the pearl polymerization of styrene
 monomer to which has been added a mixture of divinylbenzenes. A level of
 1-2% cross-linking is usually employed. Such a matrix also can be used in
 solid-phase PNA synthesis in accordance with the present invention (FIG.
 4).
 Concerning the initial functionalization of the solid phase, more than
 fifty methods have been described in connection with traditional
 solid-phase peptide synthesis (see, e.g., Barany and Merrifield in "The
 Peptides" Vol. 2, Academic Press, New York, 1979, pp. 1-284, and Stewart
 and Young, "Solid Phase Peptide Synthesis", 2nd Ed., Pierce Chemical
 Company, Ill., 1984). Reactions for the introduction of chloromethyl
 functionality (Merrifield resin; via a chloromethyl methyl
 ether/SnCl.sub.4 reaction), aminomethyl functionality (via an
 N-hydroxymethylphthalimide reaction; see, Mitchell, et al., Tetrahedron
 Lett., 1976, 3795), and benzhydrylamino functionality (Pietta, et al., J.
 Chem. Soc., 1970, 650) are the most widely applied. Regardless of its
 nature, the purpose of the functionality is normally to form an anchoring
 linkage between the copolymer solid support and the C-terminus of the
 first amino acid to be coupled to the solid support. As will be
 recognized, anchoring linkages also can be formed between the solid
 support and the amino acid N-terminus. It is generally convenient to
 express the "concentration" of a functional group in terms of millimoles
 per gram (mmol/g). Other reactive functionalities which have been
 initially introduced include 4-methylbenzhydrylamino and
 4-methoxybenzhydrylamino. All of these established methods are in
 principle useful within the context of the present invention. Preferred
 methods for PNA synthesis employ aminomethyl as the initial functionality,
 in that aminomethyl is particularly advantageous with respect to the
 incorporation of "spacer" or "handle" groups, owing to the reactivity of
 the amino group of the aminomethyl functionality with respect to the
 essentially quantitative formation of amide bonds to a carboxylic acid
 group at one end of the spacer-forming reagent. A vast number of relevant
 spacer- or handle-forming bifunctional reagents have been described (see,
 Barany, et al., Int. J. Peptide Protein Res., 1987, 30, 705), especially
 reagents which are reactive towards amino groups such as found in the
 aminomethyl function. Representative bifunctional reagents include
 4-(haloalkyl)aryl-lower alkanoic acids such as 4-(bromomethyl)phenylacetic
 acid, Boc-aminoacyl-4-(oxymethyl)aryl-lower alkanoic acids such as
 Boc-aminoacyl-4-(oxymethyl)phenylacetic acid, N-Boc-p-acylbenzhydrylamines
 such as N-Boc-p-glutaroylbenzhydrylamine, N-Boc-4'-lower
 alkyl-p-acylbenzhydrylamines such as
 N-Boc-4'-methyl-p-glutaroylbenzhydrylamine, N-Boc-4'-lower
 alkoxy-p-acylbenzhydrylamines such as
 N-Boc-4'-methoxy-p-glutaroyl-benzhydrylamine, and
 4-hydroxymethylphenoxyacetic acid. One type of spacer group particularly
 relevant within the context of the present invention is the
 phenylacetamidomethyl (Pam) handle (Mitchell and Merrifield, J. Org.
 Chem., 1976, 41, 2015) which, deriving from the electron withdrawing
 effect of the 4-phenylacetamidomethyl group, is about 100 times more
 stable than the classical benzyl ester linkage towards the Boc-amino
 deprotection reagent trifluoroacetic acid (TFA).
 Certain functionalities (e.g., benzhydrylamino, 4-methylbenzhydrylamino and
 4-methoxybenzhydrylamino) which may be incorporated for the purpose of
 cleavage of a synthesized PNA chain from the solid support such that the
 C-terminal of the PNA chain is in amide form, require no introduction of a
 spacer group. Any such functionality may advantageously be employed in the
 context of the present invention.
 An alternative strategy concerning the introduction of spacer or handle
 groups is the so-called "preformed handle" strategy (see, Tam, et al.,
 Synthesis, 1979, 955-957), which offers complete control over coupling of
 the first amino acid, and excludes the possibility of complications
 arising from the presence of undesired functional groups not related to
 the peptide or PNA synthesis. In this strategy, spacer or handle groups,
 of the same type as described above, are reacted with the first amino acid
 desired to be bound to the solid support, the amino acid being N-protected
 and optionally protected at the other side-chains which are not relevant
 with respect to the growth of the desired PNA chain. Thus, in those cases
 in which a spacer or handle group is desirable, the first amino acid to be
 coupled to the solid support can either be coupled to the free reactive
 end of a spacer group which has been bound to the initially introduced
 functionality (for example, an aminomethyl group) or can be reacted with
 the spacer-forming reagent. The space-forming reagent is then reacted with
 the initially introduced functionality. Other useful anchoring schemes
 include the "multidetachable" resins (Tam, et al., Tetrahedron Lett.,
 1979, 4935 and J. Am. Chem. Soc., 1980, 102, 611; Tam, J. Org. Chem.,
 1985, 50, 5291), which provide more than one mode of release and thereby
 allow more flexibility in synthetic design.
 Suitable choices for N-protection are the tert-butyloxycarbonyl (Boc) group
 (Carpino, J. Am. Chem. Soc., 1957, 79, 4427; McKay, et al., J. Am. Chem.
 Soc., 1957, 79, 4686; Anderson, et al., J. Am. Chem. Soc., 1957, 79, 6180)
 normally in combination with benzyl-based groups for the protection of
 side chains, and the 9-fluorenylmethyloxycarbonyl (Fmoc) group (Carpino,
 et al., J. Am. Chem. Soc., 1970, 92, 5748 and J. Org. Chem., 1972, 37,
 3404), normally in combination with tert-butyl (tBu) for the protection of
 any side chains, although a number of other possibilities exist which are
 well known in conventional solid-phase peptide synthesis. Thus, a wide
 range of other useful amino protecting groups exist, some of which are
 Adoc (Hass, et al., J. Am. Chem. Soc., 1966, 88, 1988), Bpoc (Sieber,
 Helv. Chem. Acta., 1968, 51, 614), Mcb (Brady, et al., J. Org. Chem.,
 1977, 42, 143), Bic (Kemp, et al., Tetrahedron, 1975, 4624), the
 o-nitrophenylsulfenyl (Nps) (Zervas, et al., J. Am. Chem. Soc., 1963, 85,
 3660), and the dithiasuccinoyl (Dts) (Barany, et al., J. Am. Chem. Soc.,
 1977, 99, 7363). These amino protecting groups, particularly those based
 on the widely-used urethane functionality, successfully prohibit
 racemization (mediated by tautomerization of the readily formed
 oxazolinone (azlactone) intermediates (Goodman, et al., J. Am. Chem. Soc.,
 1964, 86, 2918)) during the coupling of most .alpha.-amino acids. In
 addition to such amino protecting groups, a whole range of otherwise
 "worthless" nonurethane-type of amino protecting groups are applicable
 when assembling PNA molecules, especially those built from achiral units.
 Thus, not only the above-mentioned amino protecting groups (or those
 derived from any of these groups) are useful within the context of the
 present invention, but virtually any amino protecting group which largely
 fulfills the following requirements: (1) stability to mild acids (not
 significantly attacked by carboxyl groups); (2) stability to mild bases or
 nucleophiles (not significantly attacked by the amino group in question);
 (3) resistance to acylation (not significantly attacked by activated amino
 acids). Additionally: (4) the protecting group must be close to
 quantitatively removable, without serious side reactions, and (5) the
 optical integrity, if any, of the incoming amino acid should preferably be
 highly preserved upon coupling. Finally, the choice of side-chain
 protecting groups, in general, depends on the choice of the amino
 protecting group, since the protection of side-chain functionalities must
 withstand the conditions of the repeated amino deprotection cycles. This
 is true whether the overall strategy for chemically assembling PNA
 molecules relies on, for example, differential acid stability of amino and
 side-chain protecting groups (such as is the case for the above-mentioned
 "Boc-benzyl" approach) or employs an orthogonal, that is, chemoselective,
 protection scheme (such as is the case for the above-mentioned "Fmoc-tBu"
 approach),
 Following coupling of the first amino acid, the next stage of solid-phase
 synthesis is the systematic elaboration of the desired PNA chain. This
 elaboration involves repeated deprotection/coupling cycles. The temporary
 protecting group, such as a Boc or Fmoc group, on the last-coupled amino
 acid is quantitatively removed by a suitable treatment, for example, by
 acidolysis, such as with trifluoroacetic acid, in the case of Boc, or by
 base treatment, such as with piperidine, in the case of Fmoc, so as to
 liberate the N-terminal amine function.
 The next desired N-protected amino acid is then coupled to the N-terminal
 of the last-coupled amino acid. This coupling of the C-terminal of an
 amino acid with the N-terminal of the last-coupled amino acid can be
 achieved in several ways. For example, it can be bound by providing the
 incoming amino acid in a form with the carboxyl group activated by any of
 several methods, including the initial formation of an active ester
 derivative such as a 2,4,5-trichlorophenyl ester (Pless, et al., Helv.
 Chim. Acta, 1963, 46, 1609), a phthalimido ester (Nefkens, et al., J. Am.
 Chem. Soc., 1961, 83, 1263), a pentachlorophenyl ester (Kupryszewski,
 Rocz. Chem., 1961, 35, 595), a pentafluorophenyl ester (Kovacs, et al., J.
 Am. Chem. Soc., 1963, 85, 183), an o-nitrophenyl ester (Bodanzsky, Nature,
 1955, 175, 685), an imidazole ester (Li, et al., J. Am. Chem. Soc., 1970,
 92, 7608), and a 3-hydroxy-4-oxo-3,4-dihydroquinazoline (Dhbt-OH) ester
 (Konig, et al., Chem. Ber., 1973, 103, 2024 and 2034), or the initial
 formation of an anhydride such as a symmetrical anhydride (Wieland, et
 al., Angew. Chem., Int. Ed. Engl., 1971, 10, 336). Alternatively, the
 carboxyl group of the incoming amino acid can be reacted directly with the
 N-terminal of the last-coupled amino acid with the assistance of a
 condensation reagent such as, for example, dicyclohexylcarbodiimide
 (Sheehan, et al., J. Am. Chem. Soc., 1955, 77, 1067) or derivatives
 thereof. Benzotriazolyl N-oxy-trisdimethylaminophosphonium
 hexafluorophosphate (BOP), "Castro's reagent" (see, e.g., Rivaille, et
 al., Tetrahedron, 1980, 36, 3413) is recommended when assembling PNA
 molecules containing secondary amino groups. Finally, activated PNA
 monomers analogous to the recently-reported amino acid fluorides (Carpino,
 J. Am. Chem. Soc., 1990, 112, 9651) hold considerable promise to be used
 in PNA synthesis as well.
 Following assembly of the desired PNA chain, including protecting groups,
 the next step will normally be deprotection of the amino acid moieties of
 the PNA chain and cleavage of the synthesized PNA from the solid support.
 These processes can take place substantially simultaneously, thereby
 providing the free PNA molecule in the desired form. Alternatively, in
 cases in which condensation of two separately synthesized PNA chains is to
 be carried out, it is possible by choosing a suitable spacer group at the
 start of the synthesis to cleave the desired PNA chains from their
 respective solid supports (both peptide chains still incorporating their
 side-chain protecting groups) and finally removing the side-chain
 protecting groups after, for example, coupling the two side-chain
 protected peptide chains to form a longer PNA chain.
 In the above-mentioned "Boc-benzyl" protection scheme, the final
 deprotection of side-chains and release of the PNA molecule from the solid
 support is most often carried out by the use of strong acids such as
 anhydrous HF (Sakakibara, et al., Bull. Chem. Soc. Jpn., 1965, 38, 4921),
 boron tris (trifluoroacetate) (Pless, et al., Helv. Chim. Acta, 1973, 46,
 1609), and sulfonic acids such as trifluoromethanesulfonic acid and
 methanesulfonic acid (Yajima, et al., J. Chem. Soc., Chem. Comm., 1974,
 107). This conventional strong acid (e.g., anhydrous HF) deprotection
 method, produces very reactive carbocations that may lead to alkylation
 and acylation of sensitive residues in the PNA chain. Such side-reactions
 are only partly avoided by the presence of scavengers such as anisole,
 phenol, dimethyl sulfide, and mercaptoethanol and, therefore, the
 sulfide-assisted acidolytic S.sub.N 2 deprotection method (Tam, et al., J.
 Am. Chem. Soc., 1983, 105, 6442 and J. Am. Chem. Soc., 1986, 108, 5242),
 the so-called "low", which removes the precursors of harmful carbocations
 to form inert sulfonium salts, is frequently employed in peptide and PNA
 synthesis, either solely or in combination with "high" methods. Less
 frequently, in special cases, other methods used for deprotection and/or
 final cleavage of the PNA-solid support bond are, for example, such
 methods as base-catalyzed alcoholysis (Barton, et al., J. Am. Chem. Soc.,
 1973, 95, 4501), and ammonolysis as well as hydrazinolysis (Bodanszky, et
 al., Chem. Ind., 1964 1423), hydrogenolysis (Jones, Tetrahedron Lett. 1977
 2853 and Schlatter, et al., Tetrahedron Lett. 1977 2861)), and photolysis
 (Rich and Gurwara, J. Am. Chem. Soc., 1975 97, 1575)).
 Finally, in contrast with the chemical synthesis of "normal" peptides,
 stepwise chain building of achiral PNAs such as those based on
 aminoethylglycyl backbone units can start either from the N-terminus or
 the C-terminus, because the coupling reactions are free of racemization.
 Those skilled in the art will recognize that whereas syntheses commencing
 at the C-terminus typically employ protected amine groups and free or
 activated acid groups, syntheses commencing at the N-terminus typically
 employ protected acid groups and free or activated amine groups.
 Based on the recognition that most operations are identical in the
 synthetic cycles of solid-phase peptide synthesis (as is also the case for
 solid-phase PNA synthesis), a new matrix, PEPS, was recently introduced
 (Berg, et al., J. Am. Chem. Soc., 1989, 111, 8024 and International Patent
 Application WO 90/02749) to facilitate the preparation of large numbers of
 peptides. This matrix is comprised of a polyethylene (PE) film with
 pendant long-chain polystyrene (PS) grafts (molecular weight on the order
 of 10.sup.6). The loading capacity of the film is as high as that of a
 beaded matrix, but PEPS has the additional flexibility to suit multiple
 syntheses simultaneously. Thus, in a new configuration for solid-phase
 peptide synthesis, the PEPS film is fashioned in the form of discrete,
 labeled sheets, each serving as an individual compartment. During all the
 identical steps of the synthetic cycles, the sheets are kept together in a
 single reaction vessel to permit concurrent preparation of a multitude of
 peptides at a rate close to that of a single peptide by conventional
 methods. It was reasoned that the PEPS film support, comprising linker or
 spacer groups adapted to the particular chemistry in question, should be
 particularly valuable in the synthesis of multiple PNA molecules, these
 being conceptually simple to synthesize since only four different reaction
 compartments are normally required, one for each of the four
 "pseudo-nucleotide" units. Thus, the PEPS film support has been
 successfully tested in a number of PNA syntheses carried out in a parallel
 and substantially simultaneous fashion. The yield and quality of the
 products obtained from PEPS were comparable to those obtained by using the
 traditional polystyrene beaded support. Also, experiments with other
 geometries of the PEPS polymer such as, for example, non-woven felt,
 knitted net, sticks or microwellplates have not indicated any limitations
 of the synthetic efficacy.
 Two other methods proposed for the simultaneous synthesis of large numbers
 of peptides also apply to the preparation of multiple, different PNA
 molecules. The first of these methods (Geysen, et al., Proc. Natl. Acad.
 Sci. USA, 1984, 81, 3998) utilizes acrylic acid-grafted polyethylene-rods
 and 96-microtiter wells to immobilize the growing peptide chains and to
 perform the compartmentalized synthesis. While highly effective, the
 method is only applicable on a microgram scale. The second method
 (Houghten, Proc. Natl. Acad. Sci. USA, 1985, 82, 5131) utilizes a "tea
 bag" containing traditionally-used polymer beads. Other relevant proposals
 for multiple peptide or PNA synthesis in the context of the present
 invention include the simultaneous use of two different supports with
 different densities (Tregear, in "Chemistry and Biology of Peptides", J.
 Meienhofer, ed., Ann Arbor Sci. Publ., Ann Arbor, 1972 pp. 175-178),
 combining of reaction vessels via a manifold (Gorman, Anal. Biochem.,
 1984, 136, 397), multicolumn solid-phase synthesis (e.g. Krchnak, et al.,
 Int. J. Peptide Protein Res., 1989, 33, 209), and Holm and Meldal, in
 "Proceedings of the 20th European Peptide Symposium", G. Jung and E.
 Bayer, eds., Walter de Gruyter & Co., Berlin, 1989 pp. 208-210), and the
 use of cellulose paper (Eichler, et al., Collect. Czech. Chem. Commun.,
 1989, 54, 1746).
 While the conventional cross-linked styrene/divinylbenzene copolymer matrix
 and the PEPS support are presently preferred in the context of solid-phase
 PNA synthesis, a non-limiting list of examples of solid supports which may
 be of relevance are: (1) Particles based upon copolymers of
 dimethylacrylamide cross-linked with N,N'-bisacryloylethylenediamine,
 including a known amount of
 N-tertbutoxycarbonyl-beta-alanyl-N'-acryloylhexamethylenediamine. Several
 spacer molecules are typically added via the beta alanyl group, followed
 thereafter by the amino acid residue subunits. Also, the beta
 alanyl-containing monomer can be replaced with an acryloyl sarcosine
 monomer during polymerization to form resin beads. The polymerization is
 followed by reaction of the beads with ethylenediamine to form resin
 particles that contain primary amines as the covalently linked
 functionality. The polyacrylamide-based supports are relatively more
 hydrophilic than are the polystyrene-based supports and are usually used
 with polar aprotic solvents including dimethylformamide,
 dimethylacetamide, N-methylpyrrolidone and the like (see Atherton, et al.,
 J. Am. Chem. Soc., 1975, 97, 6584, Bioorg. Chem. 1979, 8, 351), and J. C.
 S. Perkin I 538 (1981)); (2) a second group of solid supports is based on
 silica-containing particles such as porous glass beads and silica gel. One
 example is the reaction product of
 trichloro-[3-(4-chloromethyl)phenyl]propylsilane and porous glass beads
 (see Parr and Grohmann, Angew. Chem. Internal. Ed. 1972, 11, 314) sold
 under the trademark "PORASIL E" by Waters Associates, Framingham, Mass.,
 USA. Similarly, a mono ester of 1,4-dihydroxymethylbenzene and silica
 (sold under the trademark "BIOPAK" by Waters Associates) has been reported
 to be useful (see Bayer and Jung, Tetrahedron Lett., 1970, 4503); (3) a
 third general type of useful solid supports can be termed composites in
 that they contain two major ingredients: a resin and another material that
 is also substantially inert to the organic synthesis reaction conditions
 employed. One exemplary composite (see Scott, et al., J. Chrom. Sci.,
 1971, 9, 577) utilized glass particles coated with a hydrophobic,
 cross-linked styrene polymer containing reactive chloromethyl groups, and
 was supplied by Northgate Laboratories, Inc., of Hamden, Conn., USA.
 Another exemplary composite contains a core of fluorinated ethylene
 polymer onto which has been grafted polystyrene (see Kent and Merrifield,
 Israel J. Chem. 1978, 17, 243) and van Rietschoten in "Peptides 1974", Y.
 Wolman, Ed., Wiley and Sons, New York, 1975, pp. 113-116); and (4)
 contiguous solid supports other than PEPS, such as cotton sheets (Lebl and
 Eichler, Peptide Res. 1989, 2, 232) and hydroxypropylacrylate-coated
 polypropylene membranes (Daniels, et al., Tetrahedron Lett. 1989, 4345),
 are suited for PNA synthesis as well.
 Whether manually or automatically operated, solid-phase PNA synthesis in
 the context of the present invention is normally performed batchwise.
 However, most of the syntheses may equally well be carried out in the
 continuous-flow mode, where the support is packed into columns (Bayer, et
 al., Tetrahedron Lett., 1970, 4503 and Scott, et al., J. Chromatogr. Sci.,
 1971, 9, 577). With respect to continuous-flow solid-phase synthesis, the
 rigid poly(dimethylacrylamide)-Kieselguhr support (Atherton, et al., J.
 Chem. Soc. Chem. Commun., 1981, 1151) appears to be particularly
 successful, but another valuable configuration concerns the one worked out
 for the standard copoly(styrene-1%-divinylbenzene) support (Krchnak, et
 al., Tetrahedron Lett., 1987, 4469).
 While the solid-phase technique is presently preferred in the context of
 PNA synthesis, other methodologies or combinations thereof, for example,
 in combination with the solid-phase technique, apply as well: (1) the
 classical solution-phase methods for peptide synthesis (e.g., Bodanszky,
 "Principles of Peptide Synthesis", Springer-Verlag, Berlin-New York 1984),
 either by stepwise assembly or by segment/fragment condensation, are of
 particular relevance when considering especially large scale productions
 (gram, kilogram, and even tons) of PNA compounds; (2) the so-called
 "liquid-phase" strategy, which utilizes soluble polymeric supports such as
 linear polystyrene (Shemyakin, et al., Tetrahedron Lett., 1965, 2323) and
 polyethylene glycol (PEG) (Mutter and Bayer, Angew. Chem., Int. Ed. Engl.,
 1974, 13, 88), is useful; (3) random polymerization (see, e.g., Odian,
 "Principles of Polymerization", McGraw-Hill, New York (1970)) yielding
 mixtures of many molecular weights ("polydisperse") peptide or PNA
 molecules are particularly relevant for purposes such as screening for
 antiviral effects; (4) a technique based on the use of polymer-supported
 amino acid active esters (Fridkin, et al., J. Am. Chem. Soc., 1965, 87,
 4646), sometimes referred to as "inverse Merrifield synthesis" or
 "polymeric reagent synthesis", offers the advantage of isolation and
 purification of intermediate products, and may thus provide a particularly
 suitable method for the synthesis of medium-sized, optionally protected,
 PNA molecules, that can subsequently be used for fragment condensation
 into larger PNA molecules; (5) it is envisaged that PNA molecules may be
 assembled enzymatically by enzymes such as proteases or derivatives
 thereof with novel specificities (obtained, for example, by artificial
 means such as protein engineering). Also, one can envision the development
 of "PNA ligases" for the condensation of a number of PNA fragments into
 very large PNA molecules; (6) since antibodies can be generated to
 virtually any molecule of interest, the recently developed catalytic
 antibodies (abzymes), discovered simultaneously by the groups of Lerner
 (Tramantano, et al., Science, 1986, 234, 1566) and of Schultz (Pollack, et
 al., Science, 1986, 234, 1570), should also be considered as potential
 candidates for assembling PNA molecules. Thus, there has been considerable
 success in producing abzymes catalyzing acyl-transfer reactions (see for
 example Shokat, et al., Nature, 1989, 338, 269) and references therein).
 Finally, completely artificial enzymes, very recently pioneered by
 Stewart's group (Hahn, et al., Science, 1990, 248, 1544), may be developed
 to suit PNA synthesis. The design of generally applicable enzymes,
 ligases, and catalytic antibodies, capable of mediating specific coupling
 reactions, should be more readily achieved for PNA synthesis than for
 "normal" peptide synthesis since PNA molecules will often be comprised of
 only four different amino acids (one for each of the four native
 nucleobases) as compared to the twenty natural by occurring
 (proteinogenic) amino acids constituting peptides. In conclusion, no
 single strategy may be wholly suitable for the synthesis of a specific PNA
 molecule, and therefore, sometimes a combination of methods may work best.
 EXAMPLE B
 Synthesis of Monomeric Building Blocks
 The monomers preferably are synthesized by the general scheme outlined in
 FIG. 5. This involves preparation of either the methyl or ethyl ester of
 (Bocaminoethyl)glycine, by a protection/deprotection procedure as
 described in Examples 34-36. The synthesis of thymine monomer is described
 in Examples 37-38, and that of the protected cytosine monomer is described
 in Example 39.
 The synthesis of the protected adenine monomer (FIG. 6) involved alkylation
 with ethyl bromoacetate (Example 40) and verification of the position of
 substitution by X-ray crystallography, as being the wanted 9-position. The
 N.sup.6 -amino group then was protected with the benzyloxycarbonyl group
 by the use of the reagent N-ethyl-benzyloxycarbonylimidazole
 tetrafluoroborate (Example 41). Simple hydrolysis of the product ester
 (Example 42) gave N.sup.6 -benzyloxycarbonyl-9-carboxymethyl adenine,
 which then was used in the standard procedure (Examples 43-44, FIG. 5).
 The adenine monomer has been built into two different PNA-oligomers
 (Examples 66, 67, 81 and 83).
 The synthesis of the protected G-monomer is outlined in FIG. 7. The
 starting material, 2-amino-6-chloropurine, was alkylated with bromoacetic
 acid (Example 45) and the chlorine atom was then substituted with a
 benzyloxy group (Example 46). The resulting acid was coupled to the
 (bocaminoethyl) glycine methyl ester (from Example 46) with agent
 PyBrop.TM., and the resulting ester was hydrolysed (Example 47). The
 O.sup.6 -benzyl group was removed in the final HF-cleavage step in the
 synthesis of the PNA-oligomer. Cleavage was verified by finding the
 expected mass of the final PNA-oligomer, upon incorporation into an
 PNA-oligomer using diisopropyl carbodiimide as the condensation agent
 (Examples 65 and 81).
 EXAMPLE C
 Extended Backbones
 Alterations of the groups A, C and D (FIG. 16) is demonstrated by the
 synthesis of monomeric building blocks and incorporation into
 PNA-oligomers.
 In one example, the C group was a CH(CH.sub.3) group. The synthesis of the
 corresponding monomer is outlined in FIG. 8. It involves preparation of
 Boc-protected 1-amino-2,3-propanediol (Example 48), which is cleaved by
 periodate to give bocaminoacetaldehyde, which is used directly in the next
 reaction. The bocaminoacetaldehyde can be condensed with a variety of
 amines; in Example 49, alanine ethyl ester was used. In Examples 50-52,
 the corresponding thymine monomers were prepared. The monomer has been
 incorporated into an 8-mer (Example 70) by the DCC-coupling protocol
 (Examples 66 and 67).
 In another example, the D group is a (CH.sub.2).sub.3 group. The synthesis
 of the corresponding monomer is outlined in FIG. 18.A and described in
 Examples 53-54.
 In another example, the A group is a (CH.sub.2).sub.2 CO group. The
 synthesis of the corresponding thymine monomer is outlined FIG. 18.B and
 Examples 56 through 58.
 In yet another example, the C group is a (CH.sub.2).sub.2 group. The
 synthesis of the thymine and protected cytosine monomer is outlined in
 FIG. 9 and Examples 59 through 64. Hybridization experiments with a
 PNA-oligomer containing one unit is described in Examples 71 and 91, which
 shows a significant lowering of affinity but a retention of specificity.
 GENERAL REMARKS
 The following abbreviations are used in the experimental examples: DMF,
 N,N-dimethylformamide; DCC, N,N-dicyclohexyl carbodiimide; DCU,
 N,N-dicyclohexyl urea; THF, tetrahydrofuran; aeg, N-acetyl
 (2'-aminoethyl)glycine; pfp, pentafluorophenyl; Boc, tert-butoxycarbonyl;
 Z, benzyloxycarbonyl; NMR, nuclear magnetic resonance; s, singlet; d,
 doublet; dd, doublet of doublets; t; triplet; q, quartet; m, multiplet; b,
 broad; .delta., chemical shift;
 NMR spectra were recorded on either a JEOL FX 90Q spectrometer, or a Bruker
 250 MHz with tetramethylsilane as internal standard. Mass spectrometry was
 performed on a MassLab VG 12-250 quadropole instrument fitted with a VG
 FAB source and probe. Melting points were recorded on Buchi melting point
 apparatus and are uncorrected. N,N-Dimethylformamide was dried over 4
 .ANG. molecular sieves, distilled and stored over 4 .ANG. molecular
 sieves. Pyridine (HPLC quality) was dried and stored over 4 .ANG.
 molecular sieves. Other solvents used were either the highest quality
 obtainable or were distilled before use. Dioxane was passed through basic
 alumina prior to use. Bocanhydride, 4-nitrophenol, methyl bromoacetate,
 benzyloxycarbonyl chloride, pentafluorophenol were all obtained through
 Aldrich Chemical Company. Thymine, cytosine, adenine were all obtained
 through Sigma.
 Thin layer chromatography (Tlc) was performed using the following solvent
 systems: (1) chloroform:triethyl amine:methanol, 7:1:2; (2) methylene
 chloride:methanol, 9:1; (3) chloroform:methanol:acetic acid 85:10:5. Spots
 were visualized by UV (254 nm) or/and spraying with a ninhydrin solution
 (3 g ninhydrin in 1000 ml 1-butanol and 30 ml acetic acid), after heating
 at 120.degree. C. for 5 min and, after spraying, heating again.
 EXAMPLE 11
 tert-Butyl 4-nitrophenyl carbonate
 Sodium carbonate (29.14 g; 0.275 mol) and 4-nitrophenol (12.75 g; 91.6
 mmol) were mixed with dioxane (250 ml). Boc-anhydride (20.0 g; 91.6 mmol)
 was transferred to the mixture with dioxane (50 ml). The mixture was
 refluxed for 1 h, cooled to 0.degree. C., filtered and concentrated to
 1/3, and then poured into water (350 ml) at 0.degree. C. After stirring
 for 1/2 h., the product was collected by filtration, washed with water,
 and then dried over sicapent, in vacuo. Yield 21.3 g (97%). M.p.
 73.0-74.5.degree. C. (litt. 78.5-79.5.degree. C.). Anal. for C.sub.11
 H.sub.13 NO.sub.5 found(calc.) C: 55.20(55.23) H: 5.61(5.48) N:
 5.82(5.85).
 EXAMPLE 12
 (N'-Boc-2'-aminoethyl) glycine (2)
 The title compound was prepared by a modification of the procedure by
 Heimer, et al. Int. J. Pept. , 1984, 23, 203-211 N-(2-Aminoethyl)glycine
 (1, 3.00 g; 25.4 mmol) was dissolved in water (50 ml), dioxane (50 ml) was
 added, and the pH was adjusted to 11.2 with 2 N sodium hydroxide.
 tert-Butyl-4-nitrophenyl carbonate (7.29 g; 30.5 mmol) was dissolved in
 dioxane (40 ml) and added dropwise over a period of 2 h, during which time
 the pH was maintained at 11.2 with 2 N sodium hydroxide. The pH was
 adjusted periodically to 11.2 for three more hours and then the solution
 was left overnight. The solution was cooled to 0.degree. C. and the pH was
 carefully adjusted to 3.5 with 0.5 M hydrochloric acid. The aqueous
 solution was washed with chloroform (3.times.200 ml), the pH adjusted to
 9.5 with 2N sodium hydroxide and the solution was evaporated to dryness,
 in vacuo (14 mmHg). The residue was extracted with DMF (25+2.times.10 ml)
 and the extracts filtered to remove excess salt. This results in a
 solution of the title compound in about 60% yield and greater than 95%
 purity by tlc (system 1 and visualised with ninhydrin, Rf=0.3). The
 solution was used in the following preparations of Boc-aeg derivates
 without further purification.
 EXAMPLE 13
 N-1-Carboxymethylthymine (4)
 This procedure is different from the literature synthesis, but is easier,
 gives higher yields, and leaves no unreacted thymine in the product. To a
 suspension of thymine (3, 40.0 g; 0.317 mol) and potassium carbonate (87.7
 g; 0.634 mmol) in DMF (900 ml) was added methyl bromoacetate (30.00 ml;
 0.317 mmol). The mixture was stirred vigorously overnight under nitrogen.
 The mixure was filtered and evaporated to dryness, in vacuo. The solid
 residue was treated with water (300 ml) and 4 N hydrochloric acid (12 ml),
 stirred for 15 min at 0.degree. C., filtered, and washed with water
 (2.times.75 ml). The precipitate was treated with water (120 ml) and 2N
 sodium hydroxide (60 ml), and was boiled for 10 minutes. The mixture was
 cooled to 0.degree. C., filtered, and the pure title compound was
 precipitated by the addition of 4 N hydrochloric acid (70 ml). Yield after
 drying, in vacuo over sicapent: 37.1 g (64%). .sup.1 H-NMR: (90 MHz;
 DMSO-d.sub.6): 11.33 ppm (s,1H,NH); 7.49(d,J=0.92 Hz,1H,ArH); 4.38
 (s,2H,CH.sub.2); 1.76 (d,J=0.92 Hz,T-CH.sub.3)
 EXAMPLE 14
 N-1-Carboxymethylthymine pentafluorophenyl ester (5)
 N-1-Carboxymethylthymine (4, 10.0 g; 54.3 mmol) and pentafluorophenol (10.0
 g; 54.3 mmol) were dissolved in DMF (100 ml) and cooled to 5.degree. C. in
 ice water. DCC (13.45 g; 65.2 mmol) then was added. When the temperature
 passed below 5.degree. C., the ice bath was removed and the mixture was
 stirred for 3 h at ambient temperature. The precipitated DCU was removed
 by filtration and washed twice with DMF (2.times.10 ml). The combined
 filtrate was poured into ether (1400 ml) and cooled to 0.degree. C.
 Petroleum ether (1400 ml) was added and the mixture was left overnight.
 The title compound was isolated by filtration and was washed thoroughly
 with petroleum ether. Yield: 14.8 g (78%). The product was pure enough to
 carry out the next reaction, but an analytical sample was obtained by
 recrystallization from 2-propanol. M.p. 200.5-206.degree. C. Anal. for
 C.sub.13 H.sub.7 F.sub.5 N.sub.2 O.sub.4. Found(calc.) C: 44.79(44.59); H:
 2.14(2.01) N: 8.13(8.00). FAB-MS: 443 (M+1+glycerol), 351 (M+1). .sup.1
 H-NMR (90 MHz; DMS-d.sub.6): 11.52 ppm (s,1H,NH) ; 7.64 (s,1H,ArH); 4.99
 (s,2H, CH.sub.2); 1.76 (s,3H,CH.sub.3).
 EXAMPLE 15
 1-(Boc-aeg)thymine (6)
 To the DMF-solution from above was added triethyl amine (7.08 ml; 50.8
 mmol) followed by N-1-carboxymethylthymine pentafluorophenyl ester (5,
 4.45 g; 12.7 mmol). The resultant solution was stirred for 1 h. The
 solution was cooled to 0.degree. C. and treated with cation exchange
 material ("Dowex 50W X-8", 40 g) for 20 min. The cation exchange material
 was removed by filtration, washed with dichloromethane (2.times.15 ml),
 and dichloromethane (150 ml) was added. The resulting solution was washed
 with saturated sodium chloride, dried over magnesium sulfate, and
 evaporated to dryness, in vacuo, first by a water aspirator and then by an
 oil pump. The residue was shaken with water (50 ml) and evaporated to
 dryness. This procedure was repeated once. The residue then was dissolved
 in methanol (75 ml) and poured into ether (600 ml) and petroleum ether
 (1.4 L). After stirring overnight, the white solid was isolated by
 filtration and was washed with petroleum ether. Drying over sicapent, in
 vacuo, gave 3.50 g (71.7%). M.p. 142-147.degree. C. Anal. for C.sub.16
 H.sub.24 N.sub.4 O.sub.7. Found(calc.) C: 49.59(50.00) H: 6.34(6.29) N:
 14.58(14.58). .sup.1 H-NMR (250 MHz, DMSO-d.sub.6): Due to the limited
 rotation around the secondary amide bond several of the signals were
 doubled in the ratio 2:1,(indicated in the list by mj. for major and mi.
 for minor). 12.73 ppm (b,1H, --CO.sub.2 H); 11.27 ppm (s, mj., imide);
 11.25 ppm (s, mi., imide); 7.30 ppm (s, mj., ArH); 7.26 ppm (s, mi., ArH);
 6.92 ppm (unres. t, mj., BocNH); 6.73 ppm (unres. t; mi., BocNH); 4.64 ppm
 (s, mj., T--CH.sub.2 --CO--); 4.47 ppm (s, mi., T--CH.sub.2 --CO--); 4.19
 ppm (s, mi., CONRCH.sub.2 CO.sub.2 H); 3.97 ppm (s, mj., CONRCH.sub.2
 CO.sub.2 H); 3.41-2.89 ppm (unres. m, --CH.sub.2 CH.sub.2 -- and water);
 1.75 ppm (s,3H, T--CH.sub.3); 1.38 ppm (s, 9H, t-Bu). .sup.13 C-NMR:
 170.68 ppm (CO); 170.34 (CO); 167.47 (CO); 167.08 (CO); 164.29 (CO); 150.9
 (C5"); 141.92 (C6"); 108.04 (C2'); 77.95 and 77.68 (Thy-CH.sub.2 CO);
 48.96, 47.45 and 46.70 (--CH.sub.2 CH.sub.2 -- and NCH.sub.2 CO.sub.2 H);
 37.98 (Thy-CH.sub.3); 28.07 (t-Bu). FAB-MS: 407 (M+Na.sup.+); 385
 (M+H.sup.+).
 EXAMPLE 16
 1-(Boc-aeg)thymine pentafluorophenyl ester (7, Boc-Ta-eg.OPfp)
 1-(Boc-aeg)thymine (6) (2.00 g; 5.20 mmol) was dissolved in DMF (5 ml) and
 methylene chloride (15 ml) was added. Pentafluorophenol (1.05 g; 5.72
 mmol) was added and the solution was cooled to 0.degree. C. in an ice
 bath. DDC then was added (1.29 g; 6.24 mmol) and the ice bath was removed
 after 2 min. After 3 h with stirring at ambient temperature, the
 precipitated DCU was removed by filtration and washed with methylene
 chloride. The combined filtrate was washed twice with aqueous sodium
 hydrogen carbonate and once with saturated sodium chloride, dried over
 magnesium sulfate, and evaporated to dryness, in vacuo. The solid residue
 was dissolved in dioxane (150 ml) and poured into water (200 ml) at
 0.degree. C. The title compound was isolated by filtration, washed with
 water, and dried over sicapent, in vacuo. Yield: 2.20 g (77%). An
 analytical sample was obtained by recrystallisation from 2-propanol. M.p.
 174-175.5.degree. C. Analysis for C.sub.22 H.sub.23 N.sub.4 O.sub.7
 F.sub.5, found(calc.): C: 48.22(48.01); H: 4.64(4.21); N: 9.67(10.18).
 .sup.1 H-NMR (250 MHz, CDCl.sub.3): Due to the limited rotation around the
 secondary amide bond several of the signals were doubled in the ratio 6:1
 (indicated in the list by mj. for major and mi. for minor). 7.01 ppm (s,
 mi., ArH); 6.99 ppm (s, mj., ArH); 5.27 ppm (unres. t, BocNH); 4.67 ppm
 (s, mj., T--CH.sub.2 --CO--); 4.60 ppm (s, mi., T--CH.sub.2 --CO--); 4.45
 ppm (s, mj., CONRCH.sub.2 CO.sub.2 Pfp); 4.42 ppm (s, mi., CONRCH.sub.2
 CO.sub.2 Pfp); 3.64 ppm (t,2H,BocNHCH.sub.2 CH.sub.2 --); 3.87 ppm
 ("q",2H,BocNHCH.sub.2 CH.sub.2 --); 1.44(s,9H,t-Bu). FAB-MS: 551 (10;
 M+1); 495 (10; M+1-tBu); 451 (80; -Boc).
 EXAMPLE 17
 N.sup.4 -Benzyloxycarbonyl cytosine (9)
 Over a period of about 1 h, benzyloxycarbonyl chloride (52 ml; 0.36 mol)
 was added dropwise to a suspension of cytosine (8, 20.0 g;0.18 mol) in dry
 pyridine (1000 ml) at 0.degree. C. under nitrogen in oven-dried equipment.
 The solution then was stirred overnight, after which the pyridine
 suspension was evaporated to dryness, in vacuo. Water (200 ml) and 4 N
 hydrochloric acid were added to reach pH .about.1. The resulting white
 precipitate was filtered off, washed with water and partially dried by air
 suction. The still-wet precipitate was boiled with absolute ethanol (500
 ml) for 10 min, cooled to 0.degree. C., filtered, washed thoroughly with
 ether, and dried, in vacuo. Yield 24.7 g (54%). M.p.&gt;250.degree. C. Anal.
 for C.sub.12 H.sub.11 N.sub.3 O.sub.3. Found(calc.); C: 58.59(58.77); H:
 4.55(4.52); N: 17.17(17.13). No NMR spectra were recorded since it was not
 possible to get the product dissolved.
 EXAMPLE 18
 N.sup.4 -Benzyloxycarbonyl-N.sup.1 -carboxymethyl cytosine (10)
 In a three necked round bottomed flask equipped with mechanical stirring
 and nitrogen coverage was placed methyl bromacetate (7.82 ml;82.6 mmol)
 and a suspension of N.sup.4 -benzyloxycarbonyl-cytosine (9, 21.0 g; 82.6
 mmol) and potassium carbonate (11.4 g; 82.6 mmol) in dry DMF (900 ml). The
 mixture was stirred vigorously overnight, filtered, and evaporated to
 dryness, in vacuo. Water (300 ml) and 4 N hydrochloric acid (10 ml) were
 added, the mixture was stirred for 15 minutes at 0.degree. C., filtered,
 and washed with water (2.times.75 ml). The isolated precipitate was
 treated with water (120 ml), 2N sodium hydroxide (60 ml), stirred for 30
 min, filtered, cooled to 0.degree. C., and 4 N hydrochloric acid (35 ml)
 was added. The title compound was isolated by filtration, washed
 thoroughly with water, recrystallized from methanol (1000 ml) and washed
 thoroughly with ether. This afforded 7.70 g (31%) of pure compound. The
 mother liquor from the recrystallization was reduced to a volume of 200 ml
 and cooled to 0.degree. C. This afforded an additional 2.30 g of a
 material that was pure by tlc but had a reddish color. M.p.
 266-274.degree. C. Anal. for C.sub.14 H.sub.13 N.sub.3 O.sub.5.
 Found(calc.); C: 55.41(55.45); H: 4.23(4.32); N: 14.04(13.86). .sup.1
 H-NMR (90 MHz; DMSO-d.sub.6): 8.02 ppm (d,J=7.32 Hz,1H,H-6); 7.39 (s,5H,
 Ph) 7.01 (d,J=7.32 Hz,1H, H-5); 5.19 (s,2H,PhCH.sub.2 --); 4.52 (s,2H).
 EXAMPLE 19
 N.sup.4 -Benzyloxycarbonyl-N.sup.1 -carboxymethyl-cytosine
 pentafluorophenyl ester (11)
 N.sup.4 -Benzyloxycarbonyl-N-carboxymethyl-cytosine (10, 4.00 g; 13.2 mmol)
 and pentafluorophenol (2.67 g; 14.5 mmol) were mixed with DMF (70 ml),
 cooled to 0.degree. C. with ice-water, and DCC (3.27 g; 15.8 mmol) was
 added. The ice bath was removed after 3 min and the mixture was stirred
 for 3 h at room temperature. The precipitated DCU was removed by
 filtration, washed with DMF, and the filtrate was evaporated to dryness,
 in vacuo (0.2 mmHg). The solid residue was treated with methylene chloride
 (250 ml), stirred vigorously for 15 min, filtered, washed twice with
 diluted sodium hydrogen carbonate and once with saturated sodium chloride,
 dried over magnesium sulfate, and evaporated to dryness, in vacuo. The
 solid residue was recrystallized from 2-propanol (150 ml) and the crystals
 were washed thoroughly with ether. Yield 3.40 g (55%). M.p.
 241-245.degree. C. Anal. for C.sub.20 H.sub.12 N.sub.3 F.sub.5 O.sub.5.
 Found(calc.); C: 51.56(51.18); H: 2.77(2.58); N: 9.24(8.95)..sup.1 H-NMR
 (90 MHz; CDCl.sub.3): 7.66 ppm (d,J=7.63 Hz,1H,H-6); 7.37 (s,5H,Ph); 7.31
 (d,J=7.63 Hz,1H,H-5); 5.21 (s,2H,PhCH.sub.2 --); 4.97 (s,2H,NCH.sub.2 --).
 FAB-MS: 470 (M+1)
 EXAMPLE 20
 N.sup.4 -Benzyloxycarbonyl-1-Boc-aeg-cytosine (12)
 To a solution of (N-Boc-2-aminoethyl)glycine (2) in DMF, prepared as
 described above, was added triethyl amine (7.00 ml; 50.8 mmol) and N.sup.4
 -benzyloxycarbonyl-N.sup.1 -carboxymethyl-cytosine pentafluorophenyl ester
 (11, 2.70 g; 5.75 mmol). After stirring the solution for 1 h at room
 temperature, methylene chloride (150 ml), saturated sodium chloride (250
 ml), and 4 N hydrochloric acid to pH .about.1 were added. The organic
 layer was separated and washed twice with saturated sodium chloride, dried
 over magnesium sulfate, and evaporated to dryness, in vacuo, first with a
 water aspirator and then with an oil pump. The oily residue was treated
 with water (25 ml) and was again evaporated to dryness, in vacuo. This
 procedure then was repeated. The oily residue (2.80 g) was then dissolved
 in methylene chloride (100 ml), petroleum ether (250 ml) was added, and
 the mixture was stirred overnight. The title compound was isolated by
 filtration and washed with petroleum ether. Tlc (system 1) indicated
 substantial quantities of pentafluorophenol, but no attempt was made to
 remove it. Yield: 1.72 g (59%). M.p. 156.degree. C. (decomp.). .sup.1
 H-NMR (250 MHz, CDCl.sub.3): Due to the limited rotation around the
 secondary amide bond several of the signals were doubled in the ratio 2:1,
 (indicated in the list by mj. for major and mi. for minor). 7.88 ppm
 (dd,1H,H-6); 7.39 (m,5H,Ph); 7.00 (dd,1H,H-5); 6.92 (b,1H,BocNH); 6.74
 (b,1H,ZNH)-?; 5.19 (s,2H,Ph--CH.sub.3); 4.81 ppm (s, mj., Cyt--CH.sub.2
 --CO--); 4.62 ppm (s, mi., Cyt--CH.sub.2 --CO--); 4.23 (s, mi.,
 CONRCH.sub.2 CO.sub.2 H); 3.98 ppm (s, mj., CONRCH.sub.2 CO.sub.2 H);
 3.42-3.02 (unres. m, --CH.sub.2 CH.sub.2 -- and water); 1.37 (s,9H,tBu).
 FAB-MS: 504 (M+1); 448 (M+1-tBu).
 EXAMPLE 21
 N.sup.4 -Benzyloxycarbonyl-1-Boc-aeg-cytosine pentafluorophenyl ester (13)
 N.sup.4 -Benzyloxycarbonyl-1-Boc-aeg-cytosine (12, 1.50 g; 2.98 mmol) and
 pentafluorophenol (548 mg; 2.98 mmol) was dissolved in DMF (10 ml)
 Methylene chloride (10 ml) was added, the reaction mixture was cooled to
 0.degree. C. in an ice bath, and DCC (676 mg; 3.28 mmol) was added. The
 ice bath was removed after 3 min and the mixture was stirred for 3 h at
 ambient temperature. The precipitate was isolated by filtration and washed
 once with methylene chloride. The precipitate was dissolved in boiling
 dioxane (150 ml) and the solution was cooled to 15.degree. C., whereby DCU
 precipitated. The DCU was removed by filtration and the resulting filtrate
 was poured into water (250 ml) at 0.degree. C. The title compound was
 isolated by filtration, was washed with water, and dried over sicapent, in
 vacuo. Yield 1.30 g (65%). Analysis for C.sub.29 H.sub.28 N.sub.5 O.sub.8
 F.sub.5. Found(calc.); C: 52.63(52.02); H: 4.41(4. 22); N: 10.55(10.46).
 .sup.1 H-NMR (250 MHz; DMSO-d.sub.6): showed essentially the spectrum of
 the above acid, most probably due to hydrolysis of the ester. FAB-MS: 670
 (M+1); 614 (M+1-tBu)
 EXAMPLE 22
 4-Chlorocarboxy-9-chloroacridine
 4-Carboxyacridone (6.25 g; 26.1 mmol), thionyl chloride (25 ml), and 4
 drops af DMF were heated gently under a flow of nitrogen until all solid
 material had dissolved. The solution then was refluxed for 40 min. The
 solution was cooled and excess thionyl chloride was removed in vacuo. The
 last traces of thionyl chloride were removed by coevaporation with dry
 benzene (dried over Na--Pb) twice. The remaining yellow powder was used
 directly in the next reaction.
 EXAMPLE 23
 4-(5-Methoxycarbonylpentylamidocarbonyl)-9-chloroacridine
 Methyl 6-aminohexanoate hydrochloride (4.70 g; 25.9 mmol) was dissolved in
 methylene chloride (90 ml), cooled to 0.degree. C., triethyl amine (15 ml)
 was added, and the resulting solution then was immediately added to the
 acid chloride from above. The roundbottomed flask containing the acid
 chloride was cooled to 0.degree. C. in an ice bath. The mixture was
 stirred vigorously for 30 min at 0.degree. C. and 3 h at room temperature.
 The resulting mixture was filtered to remove the remaining solids, which
 were washed with methylene chloride (20 ml). The red-brown methylene
 chloride filtrate was subsequently washed twice with saturated sodium
 hydrogen carbonate, once with saturated sodium chloride, dried over
 magnesium sulfate, and evaporated to dryness, in vacuo. To the resulting
 oily substance was added dry benzene (35 ml) and ligroin (60-80.degree.
 C., dried over Na--Pb). The mixture was heated to reflux. Activated carbon
 and celite were added and mixture was refluxed for 3 min. After
 filtration, the title compound crystallised upon cooling with magnetic
 stirring. It was isolated by filtration and washed with petroleum ether.
 The product was stored over solid potassium hydroxide. Yield 5.0 g (50%).
 EXAMPLE 24
 4-(5-Methoxycarbonylpentyl)amidocarbonyl-9-[6'-(4"-nitrobenzamido)hexylamin
 o]-aminoacridine
 4-(5-Methoxycarbonylpentylamidocarbonyl)-9-chloroacridine (1.30 g; 3.38
 mmol) and phenol (5 g) were heated to 80.degree. C. for 30 min under a
 flow of nitrogen, after which 6-(4'-nitrobenzamido)-1-hexylamine (897 mg;
 3.38 mmol) was added. The temperature raised to 120.degree. C. for 2 h.
 The reaction mixture was cooled and methylene chloride (80 ml) was added.
 The resulting solution was washed three times with 2N sodium hydroxide (60
 ml portions) and once with water, dried over magnesium sulfate, and
 evaporated to dryness, in vacuo. The resulting red oil (1.8 g) was
 dissolved in methylene chloride (40 ml), cooled to 0.degree. C. Ether (120
 ml) was added and the resultant solution was stirred overnight. This
 results in a mixture of solid material and an oil. The solid was isolated
 by filtration. The solid and the oil were re-dissolved in methylene
 chloride (80 ml) and added dropwise to cold ether (150 ml). After 20
 minutes of stirring, the title compound was isolated by filtration in the
 form of orange crystals. The product was washed with ether and dried in
 vacuo over potassium hydroxide. Yield 1.60 g (77%). M.p. 145-147.degree.
 C.
 EXAMPLE 25
 4-(5-Carboxypentyl)amidocarbonyl-9-[6'-(4"-nitrobenzamido)hexylamino]-amino
 acridine
 4-(5-Methoxycarbonylpentyl)amidocarbonyl-9-[6'-(4"-nitrobenzamido)hexylamin
 o]aminoacridine (503 mg; 0.82 mmol) was dissolved in DMF (30 ml), and 2 N
 sodium hydroxide (30 ml) was added. After stirring for 15 min, 2 N
 hydrochloric acid (35 ml) and water (50 ml) were added at 0.degree. C.
 After stirring for 30 min, the solution was decanted, leaving an oily
 substance which was dissolved in boiling methanol (150 ml), filtered and
 concentrated to 1/3 volume. To the methanol solution were added ether (125
 ml) and 5-6 drops of HCl in ethanol. The solution was decanted after 1 h
 of stirring at 0.degree. C. The oily substance was redissolved in methanol
 (25 ml) and precipitated with ether (150 ml). The title compound was
 isolated as yellow crystals after stirring overnight. Yield 417 mg (80%).
 M.p. 173.degree. C. (decomp.).
 EXAMPLE 26
 (a)
 4-(5-pentafluorophenyloxycarbonylpentyl)amidocarbonyl-9-[6-(4"-nitrobenzam
 ido)hexylamino]-aminoacridine (Acr.sup.1 Opfp)
 The acid from above (300 mg; 0.480 mmol) was dissolved in DMF (2 ml) and
 methylene chloride (8 ml) was added. Pentafluorophenol (97 mg; 0.53 mmol),
 transferred with 2.times.2 ml of the methylene chloride, was added. The
 resulting solution was cooled to 0.degree. C. after which DCC (124 mg;
 0.60 mmol) was subsequently added. The ice bath was removed after 5
 minutes and the mixture was left with stirring overnight. The precipitated
 DCU was removed by centrifugation and the centrifugate was evaporated to
 dryness, in vacuo, first by a water aspirator and then by an oil pump. The
 residue was dissolved in methylene chloride (20 ml), filtered, and
 evaporated to dryness, in vacuo. The residue was again dissolved in
 methylene chloride and petroleum ether (150 ml). A 1 ml portion of 5M HCl
 in ether was added. The solvent was removed by decanting after 30 min of
 stirring at 0.degree. C. The residual oily substance was dissolved in
 methylene chloride (100 ml). Petroleum ether (150 ml) was added and the
 mixture was left with stirring overnight. The next day the yellow
 precipitated crystalline material was isolated by filtration and was
 washed with copious amounts of petroleum ether. Yield, after drying, 300
 mg (78%). M.p. 97.5.degree. C. (decomp.) All samples showed satisfactory
 elemental analysis, .sup.1 H- and .sup.13 C-NMR and mass spectra.
 (b) Experimental for the Synthesis of PNA Compounds, cf. FIG. 4
 Materials: Boc-Lys (ClZ), benzhydrylamine-copoly(styrene-1%-divinylbenzene)
 resin (BHA resin), and
 p-methylbenzhydrylamine-copoly(styrene-1%-divinylbenzene) resin (MBHA
 resin) were purchased from Peninsula Laboratories. Other reagents and
 solvents were: Biograde trifluoroacetic acid from Halocarbon Products;
 diisopropylethylamine (99%; was not further distilled) and
 N-acetylimidazole (98%) from Aldrich; H.sub.2 O was distilled twice;
 anhydrous HF from Union Carbide; synthesis grade N,N-dimethylformamide and
 analytical grade methylene chloride (was not further distilled) from
 Merck; HPLC grade acetonitrile from Lab-Scan; purum grade anisole,
 N,N'-dicyclohexylcarbodiimide, and puriss. grade 2,2,2-trifluoroethanol
 from Fluka.
 (c) General Methods and Remarks
 Except where otherwise stated, the following applies. The PNA compounds
 were synthezised by the stepwise solid-phase approach (Merrifield, J. Am.
 Chem. Soc., 1963, 85, 2149) employing conventional peptide chemistry
 utilizing the TFA-labile tert-butyloxycarbonyl (Boc) group for "temporary"
 N-protection (Merrifield, J. Am. Chem. Soc., 1964, 86, 304) and the more
 acid-stable benzyloxycarbonyl (Z) and 2-chlorobenzyloxycarbonyl (ClZ)
 groups for "permanent" side chain protection. To obtain C-terminal amides,
 the PNAs were assembled onto the HF-labile BHA or MBHA resins (the MBHA
 resin has increased susceptibility to the final HF cleavage relative to
 the unsubstituted BHA resin (Matsueda, et al., Peptides, 1981, 2, 45). All
 reactions (except HF reactions) were carried out in manually operated
 standard solid-phase reaction vessels fitted with a coarse glass frit
 (Merrifield, et al., Biochemistry, 1982, 21, 5020). The quantitative
 ninhydrin reaction (Kaiser test), originally developed by Merrifield and
 co-workers (Sarin, et al., Anal. Biochem., 1981, 117, 147) for peptides
 containing "normal" amino acids, was successfully applied (see Table
 I-III) using the "normally" employed effective extinction coefficient
 .epsilon.=15000 M.sup.-1 cm.sup.-1 for all residues to determine the
 completeness of the individual couplings as well as to measure the number
 of growing peptide chains. The theoretical substitution S.sub.n-1 upon
 coupling of residue number n (assuming both complete deprotection and
 coupling as well as neither chain termination nor loss of PNA chains
 during the synthetic cycle) is calculated from the equation:
EQU S.sub.n =S.sub.n-1.times.(1+(S.sub.n-1.times..DELTA.MW.times.10.sup.-3
 mmol/mol)).sup.-1
 where .DELTA.MW is the gain in molecular weight ([.DELTA.MW]=g/mol) and
 S.sub.n-1 is the theoretical substitution upon coupling of the preceding
 residue n-1 ([S]=mmol/g). The estimated value (%) on the extent of an
 individual coupling is calculated relative to the measured substitution
 (unless S was not determined) and include correction for the number of
 remaining free amino groups following the previous cycle. HF reactions
 were carried out in a Diaflon HF apparatus from Toho Kasei (Osaka, Japan).
 Vydac C.sub.18 (5 .mu.m, 0.46.times.25 cm and 5 .mu.m, 1.0.times.25 cm)
 reverse-phase columns, respectively were used for analytical and
 semi-preparative HPLC on an SP8000 instrument. Buffer A was 5 vol %
 acetonitrile in water containing 445 .mu.l trifluoroacetic acid per liter,
 and buffer B was 60 vol % acetonitrile in water containing 390 .mu.l
 trifluoroacetic acid per liter. The linear gradient was 0-100% of buffer B
 in 30 min, flow rates 1.2 ml/min (analytical) and 5 ml/min
 (semi-preparative). The eluents were monitored at 215 nm (analytical) and
 230 nm (semi-preparative). Molecular weights of the PNAs were determined
 by .sup.252 Cf plasma desorption time-of-flight mass spectrometry from the
 mean of the most abundant isotopes.
 EXAMPLE 27
 Solid-Phase Synthesis of Acr.sup.1 -[Taeg].sub.15 -NH.sub.2 and Shorter
 Derivatives
 (a) Stepwise Assembly of Boc-[Taeg].sub.15 -BHA Resin
 The synthesis was initiated on 100 mg of preswollen and neutralized BHA
 resin (determined by the quantitative ninhydrin reaction to contain 0.57
 mmol NH.sub.2 /g) employing single couplings ("Synthetic Protocol 1")
 using 3.2 equivalents of BocTaeg-OPfp in about 33% DMF/CH.sub.2 Cl.sub.2.
 The individual coupling reactions were carried out by shaking for at least
 12 h in a manually operated 6 ml standard solid-phase reaction vessel and
 unreacted amino groups were blocked by acetylation at selected stages of
 the synthesis. The progress of chain elongation was monitored at several
 stages by the quantitative ninhydrin reaction (see Table I). Portions of
 protected Boc-[Taeg].sub.5 -BHA, Boc-[Taeg].sub.10 -BHA, and
 Boc-[Taeg].sub.15 -BHA resins were taken out after assembling 5, 10, and
 15 residues, respectively.

Substitution After Remaining Free Amino Groups After
 Estimated
 Deprotection (.mu.mol/g) Extent of
 Synthetic Residue (mmol/g) Single
 Coupling
 Step Coupled Measd Theoretol Coupling Acetylation (%)
 "0" 0.57
 1 BocTaeg ND 0.50 1.30 &lt;99.7
 2 BocTaeg ND 0.44 1.43 &lt;99.9
 3 BocTaeg 0.29 0.39 3.33 99.3
 4 BocTaeg 0.27 0.35 13.30 96.3
 5 BocTaeg 0.26 0.32 8.33 &gt;99.9
 6 BocTaeg ND 0.30 7.78 &gt;99.9
 7 BocaTeg ND 0.28 13.81 7.22 &lt;97.8
 8 BocTaeg ND 0.26 14.00 &lt;99.9
 9 BocTaeg ND 0.24 30.33 93.2
 10 BocTaeg 0.16 0.23 11.67 2.67 &gt;99.9
 11 BocTaeg ND 0.21 4.58 &gt;99.9
 12 BocTaeg ND 0.20 5.87 &lt;99.4
 13 BocTaeg ND 0.19 1.67 &gt;99.9
 14 BocTaeg ND 0.18 14.02 &lt;93.1
 15 BocTaeg 0.07 0.17 4.20 3.33 &gt;99.9
 (b) Synthesis of Acr.sup.1 -[Taeg].sub.15 -BHA Resin
 Following deprotection of the residual Boc-[Taeg].sub.15 -BHA resin
 (estimated dry weight is about 30 mg; .about.0.002 mmol growing chains),
 the H-[Taeg].sub.15 -BHA resin was reacted with about 50 equivalents (80
 mg; 0.11 mmol) of Acr.sup.1 -OPfp in 1 ml of about 66% DMF/CH.sub.2
 Cl.sub.2 (i.e., a 0.11 M solution of the pentafluorophenylester) in a 3 ml
 solid-phase reaction vessel. As judged by a qualitative ninhydrin
 reaction, coupling of the acridine moiety was close to quantitative.
 (c) Cleavage, Purification, and Identification of H-[Taeg].sub.5 -NH.sub.2
 A portion of protected Boc-[Taeg].sub.5 -BHA resin was treated with 50%
 trifluoroacetic acid in methylene chloride to remove the N-terminal Boc
 group (which is a precursor of the potentially harmful tert-butyl cation)
 prior to the HF cleavage. Following neutralization and washing (performed
 in a way similar to those of steps 2-4 in "Synthetic Protocol 1"), and
 drying for 2 h in vacuum, the resulting 67.1 mg (dry weight) of
 H-[Taeg].sub.5 -BHA resin was cleaved with 5 ml of HF:anisole (9:1, v/v)
 stirring at 0.degree. C. for 60 min. After removal of HF, the residue was
 stirred with dry diethyl ether (4.times.15 ml, 15 min each) to remove
 anisole, filtered under gravity through a fritted glass funnel, and dried.
 The PNA was then extracted into a 60 ml (4.times.15 ml, stirring 15 min
 each) 10% aqueous acetic acid solution. Aliquots of this solution were
 analyzed by analytical reverse-phase HPLC to establish the purity of the
 crude PNA. The main peak at 13.0 min accounted for about 93% of the total
 absorbance. The remaining solution was frozen and lyophilized to afford
 about 22.9 mg of crude material. Finally, 19.0 mg of the crude product was
 purified from five batches, each containing 3.8 mg in 1 ml of H.sub.2 O.
 The main peak was collected by use of a semi-preparative reverse-phase
 column. Acetonitrile was removed on a speed vac and the residual solution
 was frozen (dry ice) and subsequently lyophilized to give 13.1 mg of &gt;99%
 pure H-[Taeg].sub.5 -NH.sub.2. The PNA molecule readily dissolved in water
 and had the correct molecular weight based on mass spectral determination.
 For (M+H).sup.+ the calculated m/z value was 1349.3 and the measured m/z
 value was 1347.8.
 (d) Cleavage, Purification, and Identification of H-[Taeg].sub.10 -NH.sub.2
 A portion of protected Boc-[Taeg].sub.10 -BHA resin was treated as
 described in section (c) to yield 11.0 mg of crude material upon HF
 cleavage of 18.9 mg dry H-[Taeg].sub.10 -BHA resin. The main peak at 15.5
 min accounted for about 53% of the total absorbance. About 1 mg of the
 crude product was purified repeatedly (for reasons described below) to
 give approximately 0.1 mg of at least 80% but presumably &gt;99% pure
 H-[Taeg].sub.10 -NH.sub.2. A rather broad tail eluting after the target
 peak and accounting for about 20% of the total absorbance could not be
 removed (only slightly reduced) upon the repeated purification. Judged by
 the mass spectrum, which only confirms the presence of the correct
 molecular weight H-[Taeg].sub.10 -NH.sub.2, the tail phenomonen is
 ascribed to more or less well-defined aggregational/conformational states
 of the target molecule. Therefore, the crude product is likely to contain
 more than the above-mentioned 53% of the target molecule. H-[Taeg].sub.10
 -NH.sub.2 is readily dissolved in water. For (M+H).sup.+ the calculated
 m/z value was 2679.6 and the measured m/z value was 2681.5.
 (e) Cleavage, Purification, and Identification of H-[Taeg].sub.15
 -NH.sub.2.
 A portion of protected Boc-[Taeg].sub.15 -BHA resin was treated as
 described in section (c) to yield 3.2 mg of crude material upon HF
 cleavage of 13.9 mg dry H-[Taeg].sub.15 -BHA resin. The main peak at 22.6
 min was located in a broad bulge accounting for about 60% of the total
 absorbance (FIG. 12a). Again (see the preceding section), this bulge is
 ascribed to aggregational/conformational states of the target molecule
 H-[Taeg].sub.15 -NH2 since mass spectral analysis of the collected "bulge"
 did not significantly reveal the presence of other molecules. All of the
 crude product was purified collecting the "bulge" to give approximately
 2.8 mg material. For (M+Na).sup.+ the calculated m/z value was 4033.9 and
 the measured m/z value was 4032.9.
 (f) Cleavage, Purification, and Identification of Acr.sup.1 -[Taeg].sub.15
 -NH.sub.2.
 A portion of protected Acr.sup.1 -[Taeg].sub.15 -BHA resin was treated as
 described in section (b) to yield 14.3 mg of crude material upon HF
 cleavage of 29.7 mg dry Acr.sup.1 -[Taeg].sub.15 -BHA resin. Taken
 together, the main peak at 23.7 min and a "dimer" (see below) at 29.2 min
 accounted for about 40% of the total absorbance (FIG. 12b). The crude
 product was purified repeatedly to give approximately 1 mg of presumably
 &gt;99% pure Acr.sup.1 -[Taeg].sub.15 -NH.sub.2 "contaminated" with
 self-aggregated molecules eluting at 27.4 min, 29.2 min, and finally as a
 huge broad bulge eluting with 100% buffer B (FIG. 12c). This
 interpretation is in agreement with the observation that those peaks grow
 upon standing (for hours) in aqueous acetic acid solution, and finally
 precipitate out quantitatively. For (M+H).sup.+ the calculated m/z value
 was 4593.6 and the measured m/z value was 4588.7.
 (g) Synthetic Protocol 1
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 3 ml, 3.times.1
 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 3 ml,
 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v),
 3 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 3 ml, 6.times.1
 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin may be taken out
 and dried thoroughly for a quantitative ninhydrin analysis to determine
 the substitution; (6) addition of 3.2 equiv. (0.18 mmol; 100 mg)
 BocTaeg-OPfp dissolved in 1 ml CH.sub.2 Cl.sub.2 followed by addition of
 0.5 ml DMF (final concentration of pentafluorophenylester .about.0.12 M);
 the coupling reaction was allowed to proceed for a total of 12-24 h
 shaking at room temperature; (7) washing with DMF, 3 ml, 1.times.2 min;
 (8) washing with CH.sub.2 Cl.sub.2, 3 ml, 4.times.1 min; (9)
 neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v), 3 ml, 2.times.2
 min; (10) washing with CH.sub.2 Cl.sub.2, 3 ml, 6.times.1 min; (11) 2-5 mg
 sample of protected PNA-resin is taken out for a rapid qualitative
 ninhydrin test and further 2-5 mg is dried thoroughly for a quantitative
 ninhydrin analysis to determine the extent of coupling (after cycles 7,
 10, and 15 unreacted amino groups were blocked by acetylation with
 N-acetylimidazol in methylene chloride).
 EXAMPLE 28
 Solid-Phase Synthesis of Acr.sup.1 -[Taeg].sub.15 -Lys-NH.sub.2 and Shorter
 Derivatives
 (a) Stepwise Assembly of Boc-[Taeg].sub.15 -Lys(ClZ)-BHA Resin
 The synthesis was initiated by a quantitative loading (standard DCC in situ
 coupling in neat CH.sub.2 Cl.sub.2) of Boc-Lys(ClZ) onto 100 mg of
 preswollen and neutralized BHA resin (0.57 mmol NH.sub.2 /g). Further
 extension of the protected PNA chain employed single couplings ("Synthetic
 Protocol 2") for cycles 1 to 5 and cycles 10 to 15 using 3.2 equivalents
 of BocTaeg-OPfp in about 330 DMF/CH.sub.2 Cl.sub.2. Cycles 5 to 10
 employed an extra straight DCC (i.e., in situ) coupling of the free acid
 BocTaeg-OH in about 33% DMF/CH.sub.2 Cl.sub.2. All coupling reactions were
 carried out by shaking for at least 12 h in a manually operated 6 ml
 standard solid-phase reaction vessel. Unreacted amino groups were blocked
 by acetylation at the same stages of the synthesis, as was done in Example
 27. Portions of protected Boc-[Taeg].sub.5 -Lys(ClZ)-BHA and
 Boc-[Taeg].sub.10 -Lys(ClZ)-BHA resins were taken out after assembling 5
 and 10 PNA residues, respectively. As judged by the analytical HPLC
 chromatogram of the crude cleavage product from the Boc-[Taeg].sub.10
 -Lys(ClZ)-BHA resin (see section (e)), an additional "free acid" coupling
 of PNA residues 5 to 10 gave no significant improvement of the synthetic
 yield as compared to the throughout single-coupled residues in Example 27.
 (b) Synthesis of Acr.sup.1 -[Taeg].sub.10 -Lys(ClZ)-BHA Resin
 Following deprotection of a portion of Boc-[Taeg].sub.10 -Lys(ClZ)-BHA
 resin (estimated dry weight is about 90 mg; .about.0.01 mmol growing
 chains), the H-[Taeg].sub.15 -BHA resin was reacted with about 20
 equivalents (141 mg; 0.19 mmol) of Acr.sup.1 -OPfp in 1 ml of about 66%
 DMF/CH.sub.2 Cl.sub.2 in a 3 ml solid-phase reaction vessel. As judged by
 a qualitative ninhydrin reaction, coupling of the acridine moiety was
 close to quantitative.
 (c) Synthesis of Acr.sup.1 -[Taeg].sub.15 -Lys(ClZ)-BHA Resin
 Following deprotection of the residual Boc-[Taeg].sub.15 -Lys(ClZ)-BHA
 resin (estimated dry weight about 70 mg; .about.0.005 mmol growing
 chains), the H-[Taeg].sub.15 -Lys(ClZ)-BHA resin was reacted with about 25
 equivalents (91 mg; 0.12 mmol) of Acr.sup.1 -OPfp in 1 ml of about 66%
 DMF/CH.sub.2 Cl.sub.2 in a 3 ml solid-phase reaction vessel. As judged by
 a qualitative ninhydrin reaction, coupling of the acridine moiety was
 close to quantitative.
 (d) Cleavage, Purification, and Identification of H-[Taeg].sub.5
 -Lys-NH.sub.2
 A portion of protected Boc-[Taeg].sub.5 -Lys (ClZ)-BHA resin was treated as
 described in Example 27c to yield 8.9 mg of crude material upon HF
 cleavage of 19.0 mg dry H-[Taeg].sub.5 -Lys(ClZ)-BHA resin. The main peak
 at 12.2 min (eluted at 14.2 min if injected from an aqueous solution
 instead of the 10% aqueous acetic acid solution) accounted for about 90%
 of the total absorbance. About 2.2 mg of the crude product was purified to
 give approximately 1.5 mg of 99% pure H-[Taeg].sub.5 -Lys-NH.sub.2.
 (e) Cleavage, Purification, and Identification of H-[Taeg].sub.10
 -Lys-NH.sub.2
 A portion of protected Boc-[Taeg].sub.10 -Lys (ClZ)-BHA resin was treated
 as described in Example 27c to yield 1.7 mg of crude material upon HF
 cleavage of 7.0 mg dry H-[Taeg].sub.10 -Lys(ClZ)-BHA resin. The main peak
 at 15.1 min (eluted at 17.0 min if injected from an aqueous solution
 instead of the 10% aqueous acetic acid solution) accounted for about 50%
 of the total absorbance. About 1.2 mg of the crude product was purified to
 give approximately 0.2 mg of &gt;95% pure H-[Taeg].sub.10 -Lys-NH.sub.2. FIG.
 10a. For (M+H).sup.+ the calculated m/z value was 2807.8 and the measured
 m/z value was 2808.2.
 (f) Cleavage, Purification, and Identification of Acr.sup.1 -[Taeg].sub.10
 -Lys-NH.sub.2
 99.1 mg protected Acr.sup.1 -[Taeg].sub.10 -Lys(ClZ)-BHA resin (dry weight)
 was cleaved as described in Example 27c to yield 42.2 mg of crude
 material. The main peak at 25.3 min (eluted at 23.5 min if injected from
 an aqueous solution instead of the 10% aqueous acetic acid solution)
 accounted for about 45% of the total absorbance. An 8.87 mg portion of the
 crude product was purified to give approximately 5.3 mg of &gt;97% pure
 H-[Taeg].sub.10 -Lys-NH.sub.2. For (M+H).sup.+ the calculated m/z value
 was 2850.8 and the measured m/z value was 2849.8.
 (g) Cleavage and Purification of Acr.sup.1 -[Taeg].sub.15 -Lys-NH.sub.2
 A 78.7 mg portion of protected Acr.sup.1 -[Taeg].sub.15 -Lys(ClZ)-BHA resin
 (dry weight) was cleaved as described in Example 27(c) to yield 34.8 mg of
 crude material. The main peak at 23.5 min (about the same elution time if
 injected from an aqueous solution instead of the 10% aqueous acetic acid
 solution) and a "dimer" at 28.2 min accounted for about 35% of the total
 absorbance. About 4.5 mg of the crude product was purified to give
 approximately 1.6 mg of presumably &gt;95% pure H-[Taeg].sub.10
 -Lys-NH.sub.2. This compound could not be free of the "dimer" peak, which
 grew upon standing in aqueous acetic acid solution.
 (h) Synthetic Protocol 2
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 3 ml, 3.times.1
 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 3 ml,
 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v),
 3 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 3 ml, 6.times.1
 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin can be taken out
 and dried thoroughly for a qualitative ninhydrin analysis; (6) for cycles
 1 to 5 and cycles 10 to 15 the coupling reaction was carried out by
 addition of 3.2 equiv. (0.18 mmol; 100 mg) BocTaeg-OPfp dissolved in 1 ml
 CH.sub.2 Cl.sub.2 followed by addition of 0.5 ml DMF (final concentration
 of pentafluorophenylester .about.0.12 M); the coupling reaction was
 allowed to proceed for a total of 12-24 h with shaking; cycles 5 to 10
 employed an additional 0.12 M DCC coupling of 0.12 M BocTaeg-OH in 1.5 ml
 DMF/CH.sub.2 Cl.sub.2 (1:2, v/v); (7) washing with DMF, 3 ml, 1.times.2
 min; (8) washing with CH.sub.2 Cl.sub.2, 3 ml, 4.times.1 min; (9)
 neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v), 3 ml, 2.times.2
 min; (10) washing with CH.sub.2 Cl.sub.2, 3 ml, 6.times.1 min; (11) 2-5 mg
 sample of protected PNA-resin is taken out for a qualitative ninhydrin
 test (after cycles 7, 10, and 15 unreacted amino groups were blocked by
 acetylation with N-acetylimidazol in methylene chloride).
 EXAMPLE 29
 Improved Solid-Phase Synthesis of H-[Taeg].sub.10 -Lys-NH.sub.2
 The protected PNA was assembled onto an MBHA resin, using approximately
 half the loading of the BHA resin used in the previous examples.
 Furthermore, all cycles except one was followed by acetylation of
 uncoupled amino groups. The following describes the synthesis in full
 detail:
 (a) Preparation of Boc-Lys(ClZ)-NH-CH(p-CH.sub.3 -C.sub.6 H.sub.4)-C.sub.6
 H.sub.4 Resin (MBHA Resin) with an Initial Substitution of 0.3 mmol/g
 The desired substitution of Boc-Lys(ClZ)-MBHA resin was 0.25-0.30 mmol/g.
 In order to get this value, 1.5 mmol of Boc-Lys(ClZ) was coupled to 5.0 g
 of neutralized and preswollen MBHA resin (determined by the quantitative
 ninhydrin reaction to contain 0.64 mmol NH.sub.2 /g) using a single "in
 situ" coupling (1.5 mmol of DCC) in 60 ml of CH.sub.2 Cl.sub.2. The
 reaction was carried out by shaking for 3 h in a manually operated, 225
 ml, standard, solid-phase reaction vessel. Unreacted amino groups were
 then blocked by acetylation with a mixture of acetic
 anhydride/pyridine/CH.sub.2 Cl.sub.2 (1:1:2, v/v/v) for 18 h. A
 quantitative ninhydrin reaction on the neutralized resin showed that only
 0.00093 mmol/g free amine remained (see Table I), i.e. 0.15% of the
 original amino groups. The degree of substitution was estimated by
 deprotection and ninhydrin analysis, and was found to be 0.32 mmol/g for
 the neutralized H-Lys (ClZ)-MBHA resin. This compares well with the
 maximum value of 0.28 mmol/g for a quantitative coupling of 0.30 mmol
 Boc-Lys(ClZ)/g resin (see Table II).
 (b) Stepwise Assembly of Boc-[Taeg].sub.3 -Lys(ClZ)-MBHA Resin
 The entire batch of H-Lys(ClZ)-MBHA resin prepared in section (a) was used
 directly (in the same reaction vessel) to assemble Boc-[Taeg].sub.3
 -Lys(ClZ)-MBHA resin by single couplings ("Synthetic Protocol 3")
 utilizing 2.5 equivalents of BocTaeg-OPfp in neat CH.sub.2 Cl.sub.2. The
 quantitative ninhydrin reaction was appplied throughout the synthesis (see
 Table II).
 (c) Stepwise Assembly of Boc-[Taeg].sub.8 -Lys(ClZ)-MBHA Resin
 About 4.5 g of wet Boc-[Taeg].sub.3 -Lys(ClZ)-MBHA resin (.about.0.36 mmol
 growing chains; taken out of totally .about.19 g wet resin prepared in
 section (b)) was placed in a 55 ml SPPS reaction vessel. Boc-[Taeg].sub.8
 -Lys(ClZ)-MBHA resin was assembled by single couplings ("Synthetic
 Protocol 4") utilizing 2.5 equivalents of BocTaeg-OPfp in about 30%
 DMF/CH.sub.2 Cl.sub.2. The progress of the synthesis was monitored at all
 stages by the quantitative ninhydrin reaction (see Table II).
 (d) Stepwise Assembly of Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg].sub.8 -Lys(ClZ)-MBHA resin (.about.0.09 mmol
 growing chains; taken out of totally .about.4 g wet resin prepared in
 section (c)) was placed in a 20 ml SPPS reaction vessel. Boc-[Taeg].sub.10
 -Lys(ClZ)-MBHA resin was assembled by the single-coupling protocol
 employed in the preceding section utilizing 2.5 equivalents of
 BocTaeg-OPfp in about 30% DMF/CH.sub.2 Cl.sub.2. The reaction volume was 3
 ml (vigorous shaking). The synthesis was monitored by the quantitative
 ninhydrin reaction (see Table II).

Substitution After Remaining Free Amino Groups After
 Estimated
 Deprotection (.mu.mol/g) Extent of
 Synthetic Residue (mmol/g) Single
 Coupling
 Step Coupled Measd Theoret Coupling Acetylation (%)
 "0" BocLys(CIZ) 0.32 0.28 0.93
 1 BocTaeg 0.23 0.26 0.97 0.54 &gt;99.9
 2 BocTaeg 0.21 0.24 0.92 0.46 99.8
 3 BocTaeg 0.19 0.23 1.00 0.57 99.7
 4 BocTaeg 0.18 0.21 1.85 99.3
 5 BocTaeg 0.17 0.20 2.01 0.19 99.9
 6 BocTaeg 0.15 0.19 1.69 0.10 99.0
 7 BocaTeg 0.11 0.18 1.11 0.66 99.1
 8 BocTaeg 0.12 0.17 1.82 0.44 99.0
 9 BocTaeg 0.10 0.17 5.63 0.56 94.8
 10 BocTaeg 0.11 0.16 1.54 0.67 99.1
 (e) Synthesis of Ac-[Taeg].sub.10 -Lys(ClZ)-MBHA Resin
 Following deprotection of a portion of Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA
 resin (estimated dry weight is about 45 mg), the resin was next acetylated
 quantitatively with a 2 ml mixture of acetic anhydride/pyridine/CH.sub.2
 Cl.sub.2 (1:1:2, v/v/v) for 2 h in a 3 ml solid-phase reaction vessel.
 (f) Cleavage, Purification, and Identification of H-[Taeg].sub.10
 -Lys-NH.sub.2
 A portion of protected Boc-[Taeg].sub.10 -Lys(ClZ)-BHA resin was treated as
 described in Example 27c to yield about 24 mg of crude material upon HF
 cleavage of 76 mg dry H-[Taeg].sub.5 -Lys(ClZ)-BHA resin. The main peak at
 15.2 min (which includes impurities such as deletion peptides and various
 byproducts) accounted for about 78% of the total absorbance. The main peak
 also accounted for about 88% of the "main peak plus deletion peaks"
 absorbance, which is in good agreement with the overall estimated coupling
 yield of 90.1% obtained by summarizing the individual coupling yields in
 Table II. A 7.2 mg portion of the crude product was purified from two
 batches by use of a semi-preparative reserse-phase column, (collecting the
 main peak in a beaker cooled with dry ice/2-propanol). Each contained 3.6
 mg in 1 ml of H.sub.2 O. The frozen solution was lyophilized directly
 (without prior removal of acetonitrile on a speed vac) to give 4.2 mg of
 82% pure H-[Taeg].sub.10 -Lys-NH.sub.2.
 (g) Cleavage, Purification, and Identification of Ac-[Taeg].sub.10
 -Lys-NH.sub.2
 A 400.0 mg portion of protected Ac-[Taeg].sub.10 -Lys(ClZ)-BHA resin (dry
 weight) was cleaved as described in Example 27c, except for the TFA
 treatment to yield 11.9 mg of crude material. The main peak at 15.8 min
 accounted for about 75% of the total absorbance. A 4.8 mg portion of the
 crude product was purified to give approximately 3.5 mg of &gt;95% pure
 Ac-[Taeg].sub.10 -Lys-NH.sub.2. For (M+H).sup.+ the calculated m/z
 value=2849.8 and the measured m/z value=2848.8.
 (h) Synthetic Protocol 3.
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 100 ml,
 3.times.1 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 100
 ml, 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19,
 v/v), 100 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 100 ml,
 6.times.1 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin is
 taken out and dried thoroughly for a quantitative ninhydrin analysis to
 determine the substitution; (6) addition of 2.5 equiv. (3.75 mmol; 2.064
 g) BocTaeg-OPfp dissolved in 35 ml CH.sub.2 Cl.sub.2 (final concentration
 of pentafluorophenylester .about.0.1 M); the coupling reaction was allowed
 to proceed for a total of 20-24 h with shaking; (7) washing with DMF, 100
 ml, 1.times.2 min (to remove precipitate of BocTaeg-OH); (8) washing with
 CH.sub.2 Cl.sub.2, 100 ml, 4.times.1 min; (9) neutralization with
 DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v), 100 ml, 2.times.2 min; (10) washing
 with CH.sub.2 Cl.sub.2, 100 ml, 6.times.1 min; (11) 2-5 mg sample of
 protected PNA-resin is taken out for a rapid qualitative ninhydrin test
 and a further 2-5 mg is dried thoroughly for a quantitative ninhydrin
 analysis to determine the extent of coupling; (12) blocking of unreacted
 amino groups by acetylation with a 100 ml mixture of acetic
 anhydride/pyridine/CH.sub.2 Cl.sub.2 (1:1:2, v/v/v) for 2 h; (13) washing
 with CH.sub.2 Cl.sub.2, 100 ml, 6.times.1 min; (14) 2.times.2-5 mg samples
 of protected PNA-resin are taken out, neutralized with DIEA/CH.sub.2
 Cl.sub.2 (1:19, v/v) and washed with CH.sub.2 Cl.sub.2 for qualitative and
 quantitative ninhydrin analyses.
 (i) Synthetic Protocol 4.
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 25 ml,
 3.times.1 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 25
 ml, 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1:19,
 v/v), 25 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 25 ml,
 6.times.1 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin is
 taken out and dried thoroughly for a quantitative ninhydrin analysis to
 determine the substitution; (6) addition of 2.5 equiv. (0.92 mmol; 0.506
 g) BocTaeg-OPfp dissolved in 6 ml CH.sub.2 Cl.sub.2 followed by addition
 of 3 ml DMF (final concentration of pentafluorophenylester .about.0.1 M);
 the coupling reaction was allowed to proceed for a total of 20-24 hrs with
 shaking; (7) washing with DMF, 25 ml, 1.times.2 min; (8) washing with
 CH.sub.2 Cl.sub.2, 25 ml, 4.times.1 min; (9) neutralization with
 DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v), 25 ml, 2.times.2 min; (10) washing
 with CH.sub.2 Cl.sub.2, 25 ml, 6.times.1 min; (11) 2-5 mg sample of
 protected PNA-resin is taken out for a rapid qualitative ninhydrin test
 and a further 2-5 mg is dried thoroughly for a quantitative ninhydrin
 analysis to determine the extent of coupling; (12) blocking of unreacted
 amino groups by acetylation with a 25 ml mixture of acetic
 anhydride/pyridine/CH.sub.2 Cl.sub.2 (1:1:2, v/v/v) for 2 h (except after
 the first cycle); (13) washing with CH.sub.2 Cl.sub.2, 25 ml, 6.times.1
 min; (14) 2.times.2-5 mg samples of protected PNA-resin are taken out,
 neutralized with DIEA/CH.sub.2 Cl.sub.2 (1:19, v/v) and washed with
 CH.sub.2 Cl.sub.2 for qualitative and quantitative ninhydrin analyses.
 EXAMPLE 30
 Solid-Phase Synthesis of H-[Taeg].sub.5 -Caeg-[Taeg].sub.4 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.5 -C(z) aeg-[Taeg].sub.4
 -Lys(ClZ)-MBHA Resin
 About 2.5 g of wet Boc-[Taeg].sub.3 -Lys(ClZ)-MBHA resin (.about.1/6 of the
 total remaining about 16 g wet resin; .about.0.75 g dry resin .about.0.15
 mmol growing chains) was placed in a 6 ml SPPS reaction vessel.
 Boc-[Taeg].sub.5 -Caeg-[Taeg].sub.4 -Lys(ClZ)-MBHA resin was assembled by
 double coupling of all Taeg-residues utilizing the usual 2.5 equivalents
 of BocTaeg-OPfp in 2.5 ml about 30% DMF/CH.sub.2 Cl.sub.2, except that the
 first residue was single-coupled. Incorporation of the C(Z)aeg-residue was
 accomplished by coupling with 2.0 equivalents of BocC(Z)aeg-OPfp in
 TFE/CH.sub.2 Cl.sub.2 (1:2, v/v). The progress of the synthesis was
 monitored at all stages by the quantitative ninhydrin reaction (see Table
 III).

Remaining Free Amino
 Substitution After Groups After
 Deprotection (.mu.mol/g) Estimated
 Synthetic Residue (mmol/g) 1st 2nd Acetyl- Extent
 of
 Step Coupled Measd. Theoret. Coupl Coupl ation
 Coupling
 3 0.19 0.23 1.00 0.57
 4 BocTaeg 0.17 0.21 4.88 97.3 97.3
 5 BocC(Z)aeg 0.11 0.20 70.20 27.98 1.33 78.4
 (46)
 6 BocTaeg 0.10 0.19 24.79 4.58 2.40 95.4
 (75)
 7 BocTaeg 0.09 0.18 8.55 1.61 0.20 &gt;99.9
 (93)
 8 BocTaeg 0.08 0.17 6.53 0.80 0.45 99.0
 (91)
 9 BocTaeg 0.07 0.16 9.26 3.66 0.61 94.8
 (86)
 10 BocTaeg 0.07 0.15 5.32 1.48 0.60 98.8 (93)
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.5
 -Caeg-[Taeg].sub.4 -Lys -NH.sub.2
 A portion of protected Boc-[Taeg].sub.5 -Caeg-[Taeg].sub.4 -Lys(ClZ)-BHA
 resin was treated as described in Example 27(c) to yield about 14.4 mg of
 crude material upon HF cleavage of 66.9 mg dry H-[Taeg].sub.5
 -Caeg-[Taeg].sub.4 -Lys(ClZ)-BHA resin. The main peak at 14.5 min
 accounted for &gt;50% of the total absorbance. A 100.0 mg portion of the
 crude product was purified (8 batches; each dissolved in 1 ml H.sub.2 O)
 to give approximately 9.1 mg of 96% pure H-[Taeg].sub.5 -Caeg-[Taeg].sub.4
 -Lys-NH.sub.2 (FIG. 10b). For (M+H).sup.+ the calculated m/z value=2793,8
 and the measured m/z value=2790,6.
 EXAMPLE 31
 Binding of Acr.sup.1 -(Taeg).sub.10 -Lys-NH.sub.2 to dA.sub.10 (FIG. 11)
 Acr.sup.1 -(Taeg).sub.10 -Lys (100 ng) was incubated for 15 min at room
 temperature with 50 cps 5'-[.sup.32 P]-end-labelled oligonucleotide
 [d(GATCCA.sub.10 G)] in 20 .mu.l TE buffer (10 mM Tris-HCl, 1 mM EDTA, pH
 7.4). The sample was cooled in ice (15 min) and analyzed by gel
 electrophoresis in polyacrylamide (PAGE). To 10 .mu.l of the sample was
 added 2 .mu.l 50% glycerol, 5 TBE (TBE=90 mM Tris-borate, 1 mM EDTA, pH
 8.3), and the sample was analysed by PAGE (15% acrylamide, 0.5%
 bisacrylamide) in TBE buffer at 4.degree. C. A 10 .mu.l portion of the
 sample was lyophilized and redissolved in 10 .mu.l 80% formamide, 1 TBE,
 heated to 90.degree. C. (5 min), and analyzed by urea/PAGE (15%
 acrylamide, 0.5% bisacrylamide, 7 M urea) in TBE. [.sup.32 P]-containing
 DNA bands were visualized by autoradiography using intensifying screens
 and Agfa Curix RPI X-ray films exposed at -80.degree. C. for 2 h.
 Oligonucleotides were synthesized on a Biosearch 7500 DNA synthesizer,
 labelled with .gamma.[.sup.32 P]-ATP (Amersham, 5000 Ci/mmol) and
 polynucleotide kinase, and purified by PAGE using standard techniques
 (Maniatis et al. (1986): A laboratory manual, Cold Spring Harbor
 Laboratories).
 EXAMPLE 32
 Formation of Strand Displacement Complex
 A dA.sub.10 -dT.sub.10 target sequence contained within a plasmid DNA
 sequence was constructed by cloning of two oligonucleotides
 (d(GATCCA.sub.10 G) (SEQ ID NO: 9)+d(GATCCT.sub.10 G)) (SEQ ID NO: 10)
 into the BamHI restriction enzyme site of pUC19 using the Eschericia coli
 JM101 strain by standard techniques (Maniatis et al., 1986). The desired
 plasmid (designated pT10) was isolated from one of the resulting clones
 and purified by the alkaline extraction procedure and CsCl centrifugation
 (Maniatis et al., 1986). A 3'-[.sup.32 P]-end-labelled DNA fragment of 248
 bp containing the dA.sub.10 /dT.sub.10 target sequence was obtained by
 cleaving the pT10 DNA with restriction enzymes EcoRI and PvuII, labelling
 of the cleaved DNA with .alpha.[.sup.32 P]-dATP (4000 Ci/mmol, Amersham)
 using the Klenow fragment of E. coli DNA polymerase (Boehringer Mannheim),
 and purifying the 248 bp DNA fragment by PAGE (5% acrylamide, 0.06%
 bisacrylamide, TBE buffer). This DNA fragment was obtained with
 [32P]-end-labelling at the 5'-end by treating the EcoRI-cleaved pT10
 plasmid with bacterial alkaline phosphatase (Boehringer Mannheim),
 purifying the plasmid DNA by gel electrophoresis in low melting agarose,
 and labelling with .gamma.[32P] ATP and polynucleotide kinase. Following
 treatment with PvuII, the 248 bp DNA fragment was purified as above.
 The complex between Acr.sup.1 -(Taeg).sub.10 -Lys-NH.sub.2 and the 248 bp
 DNA fragment was formed by incubating 50 ng of Acr.sup.1 -(Taeg).sub.10
 -Lys-NH.sub.2 with 500 cps .sup.32 P-labelled 248 bp fragment and 0.5
 .mu.g calf thymus DNA in 100 .mu.l buffer for 60 min at 37.degree. C.
 EXAMPLE 33
 Probing of Strand Displacement Complex with:
 (a) Staphylococcus Nuclease (FIG. 12b)
 The strand displacement complex was formed in 25 mM Tris-HCl, 1 mM
 MgCl.sub.2, 0.1 mM CaCl.sub.2, pH 7.4 as described above. The complex was
 treated with Staphylococcus nuclease (Boehringer Mannheim) at 750 U/ml for
 5 min at 20.degree. C. and the reaction was stopped by addition of EDTA to
 25 mM. The DNA was precipitated with 2 vols. of ethanol, 2% potassium
 acetate redissolved in 80% formamide, TBE, heated to 90.degree. C. (5
 min), and analyzed by high resolution PAGE (10% acrylamide, 0.3%
 bisacrylamide, 7 M urea) and autoradiography.
 (b) Affinity Photocleavage (FIG. 12a+12b)
 The complex was formed in TE buffer. A sample contained in an Eppendorf
 tube was irradiated from above at 300 nm (Philips TL 20 W/12 fluorescent
 light tube, 24 Jm.sup.-2 s.sup.-1) for 30 min. The DNA was precipitated as
 above, taken up in 1 M piperidine, and heated to 90.degree. C. for 20 min.
 Following lyophilization, the DNA was analysed by PAGE as above.
 (c) Potassium Permanganate (FIG. 12b)
 The complex was formed in 100 .mu.l TE and 5 .mu.l 20 mM KMnO.sub.4 was
 added. After 15 s at 20.degree. C., the reaction was stopped by addition
 of 50 .mu.l 1.5 M sodium acetate, pH 7.0, 1 M 2-mercaptoethanol. The DNA
 was precipitated, treated with piperidine and analyzed, as above.
 (d) Photofootprinting (FIG. 12b)
 The complex was formed in 100 .mu.l TE and diazo-linked acridine (0.1
 .mu.g/.mu.l) (DHA, Nielsen et al. (1988) Nucl. Acids Res. 16, 3877-88) was
 added. The sample was irradiated at 365 nm (Philips TL 20 W/09N, 22
 Jm.sup.-2 s.sup.-1) for 30 min and treated as described for "affinity
 photocleavage".
 (e) S.sub.1 -nuclease (FIG. 12c)
 The complex was formed in 50 mM sodium acetate, 200 mM NaCl, 0.5% glycerol,
 1 mM ZnCl.sub.2, pH 4.5 and treated with nuclease S.sub.1 (Boehringer
 Mannheim) at 0.5 U/ml for 5 min at 20.degree. C. The reaction was stopped
 and treated further as described under "Staphylococcus nuclease".
 EXAMPLE 34
 N-Benzyloxycarbonyl-N-'(bocaminoethyl)glycine.
 Aminoethyl glycine (52.86 g; 0.447 mol) was dissolved in water (900 ml) and
 dioxane (900 ml) was added. The pH was adjusted to 11.2 with 2N NaOH.
 While the pH was kept at 11.2, tert-butyl-p-nitrophenyl carbonate (128.4
 g; 0.537 mol) was dissolved in dioxane (720 ml) and added dropwise over
 the course of 2 hours. The pH was kept at 11.2 for at least three more
 hours and then left with stirring overnight. The yellow solution was
 cooled to 0.degree. C. and the pH was adjusted to 3.5 with 2 N HCl. The
 mixture was washed with chloroform (4.times.100 ml), and the pH of the
 aqueous phase was readjusted to 9.5 with 2 N NaOH at 0.degree. C.
 Benzyloxycarbonyl chloride (73.5 ml; 0.515 mol) was added over half an
 hour, while the pH was kept at 9.5 with 2 N NaOH. The pH was adjusted
 frequently over the next 4 hours, and the solution was left with stirring
 overnight. On the following day the solution was washed with ether
 (3.times.600 ml) and the pH of the solution was afterwards adjusted to 1.5
 with 2 N HCl at 0.degree. C. The title compound was isolated by extraction
 with ethyl acetate (5.times.1000 ml). The ethyl acetate solution was dried
 over magnesium sulfate and evaporated to dryness, in vacuo. This afforded
 138 g, which was dissolved in ether (300 ml) and precipitated by the
 addition of petroleum ether (1800 ml). Yield 124.7 g (79%). M.p.
 64.5-85.degree. C. Anal. for C.sub.17 H.sub.24 N.sub.2 O.sub.6
 found(calc.) C: 58.40(57.94); H: 7.02(6.86); N: 7.94(7.95). .sup.1 H-NMR
 (250 MHz, CDCl.sub.3) 7.33 & 7.32 (5H, Ph); 5.15 & 5.12 (2H, PhCH.sub.2);
 4.03 & 4.01 (2H, NCH.sub.2 CO.sub.2 H); 3.46 (b, 2H, BocNHCH.sub.2
 CH.sub.2); 3.28 (b, 2H, BocNHCH.sub.2 CH.sub.2); 1.43 & 1.40 (9H, .sup.t
 Bu). HPLC (260 nm) 20.71 min. (80.2%) and 21.57 min. (19.8%). The
 UV-spectra (200 nm-300 nm) are identical, indicating that the minor peak
 consists of Bis-Z-AEG.
 EXAMPLE 35
 N'-Boc-aminoethyl glycine ethyl ester
 N-Benzyloxycarbonyl-N'-(bocaminoethyl)glycine (60.0 g; 0.170 mol) and
 N,N-dimethyl-4-aminopyridine (6.00 g) were dissolved in absolute ethanol
 (500 ml), and cooled to 0.degree. C. before the addition of DCC (42.2 g;
 0.204 mol). The ice bath was removed after 5 minutes and stirring was
 continued for 2 more hours. The precipitated DCU (32.5 g dried) was
 removed by filtration and washed with ether (3.times.100 ml). The combined
 filtrate was washed successively with diluted potassium hydrogen sulfate
 (2.times.400 ml), diluted sodium hydrogencarbonate (2.times.400 ml) and
 saturated sodium chloride (1.times.400 ml). The organic phase was
 filtered, then dried over magnesium sulfate, and evaporated to dryness, in
 vacuo, which yielded 66.1 g of an oily substance which contained some DCU.
 The oil was dissolved in absolute ethanol (600 ml) and was added 10%
 palladium on carbon (6.6 g) was added. The solution was hydrogenated at
 atmospheric pressure, where the reservoir was filled with 2 N sodium
 hydroxide. After 4 hours, 3.3 L was consumed out of the theoretical 4.2 L.
 The reaction mixture was filtered through celite and evaporated to
 dryness, in vacuo, affording 39.5 g (94%) of an oily substance. A 13 g
 portion of the oily substance was purified by silica gel (600 g SiO.sub.2)
 chromatography. After elution with 300 ml 20% petroleum ether in methylene
 chloride, the title compound was eluted with 1700 ml of 5% methanol in
 methylene chloride. The solvent was removed from the fractions with
 satisfactory purity, in vacuo and the yield was 8.49 g. Alternatively 10 g
 of the crude material was purified by Kugel Rohr distillation. .sup.1
 H-NMR (250 MHz, CD.sub.3 OD); 4.77 (b. s, NH); 4.18 (q, 2H, MeCH.sub.2
 --); 3.38 (s, 2H, NCH.sub.2 CO.sub.2 Et); 3.16 (t, 2H, BocNHCH.sub.2
 CH.sub.2); 2.68 (t, 2H, BocNHCH.sub.2 CH.sub.2); 1.43 (s, 9H, .sup.t Bu)
 and 1.26 (t, 3H, CH.sub.3) .sup.13 C-NMR 171.4 (COEt); 156.6 (CO); 78.3
 ((CH.sub.3).sub.3 C); 59.9 (CH.sub.2); 49.0 (CH.sub.2); 48.1 (CH.sub.2);
 39.0 (CH.sub.2); 26.9 (CH.sub.2) and 12.6 (CH.sub.3).
 EXAMPLE 36
 N'-Boc-aminoethyl glycine methyl ester
 The above procedure was used, with methanol being substituted for ethanol.
 The final product was purified by column purification.
 EXAMPLE 37
 1-(Boc-aeg)thymine ethyl ester
 N'-Boc-aminoethyl glycine ethyl ester (13.5 g; 54.8 mmol), DhbtOH (9.84 g;
 60.3 mmol) and 1-carboxymethyl thymine (11.1 g; 60.3 mmol) were dissolved
 in DMF (210 ml). Methylene chloride (210 ml) then was added. The solution
 was cooled to 0.degree. C. in an ethanol/ice bath and DCC (13.6 g; 65.8
 mmol) was added. The ice bath was removed after 1 hour and stirring was
 continued for another 2 hours at ambient temperature. The precipitated DCU
 was removed by filtration and washed twice with methylene chloride
 (2.times.75 ml). To the combined filtrate was added more methylene
 chloride (650 ml). The solution was washed successively with diluted
 sodium hydrogen carbonate (3.times.500 ml), diluted potassium hydrogen
 sulfate (2.times.500 ml), and saturated sodium chloride (1.times.500 ml).
 Some precipitate was removed from the organic phase by filtration. The
 organic phase was dried over magnesium sulfate and evaporated to dryness,
 in vacuo. The oily residue was dissolved in methylene chloride (150 ml),
 filtered, and the title compound was precipitated by the addition of
 petroleum ether (350 ml) at 0.degree. C. The methylene chloride/petroleum
 ether procedure was repeated once. This afforded 16.0 g (71) of a material
 which was more than 99% pure by HPLC.
 EXAMPLE 38
 1-(Boc-aeg)thymine
 The material from above was suspended in THF (194 ml, gives a 0.2 M
 solution), and 1 M aqueous lithium hydroxide (116 ml) was added. The
 mixture was stirred for 45 minutes at ambient temperature and then
 filtered to remove residual DCU. Water (40 ml) was added to the solution
 which was then washed with methylene chloride (300 ml). Additional water
 (30 ml) was added, and the alkaline solution was washed once more with
 methylene chloride (150 ml). The aqueous solution was cooled to 0.degree.
 C. and the pH was adjusted to 2 by the dropwise addition of 1 N HCl
 (approx. 110 ml). The title compound was extracted with ethyl acetate
 (9.times.200 ml), the combined extracts were dried over magnesium sulfate
 and were evaporated to dryness, in vacuo. The residue was evaporated once
 from methanol, which after drying overnight afforded a colorless glassy
 solid. Yield 9.57 g (64%). HPLC &gt;98% R.sub.T =14.8 min . Anal. for
 C.sub.16 H.sub.24 N.sub.4 O.sub.7.degree.0.25 H.sub.2 O Found (calc.) C:
 49.29(49.42); H: 6.52(6.35); N: 14.11(14.41). Due to the limited rotation
 around the secondary amide, several of the signals were doubled in the
 ratio 2:1 (indicated in the list by mj. for major and mi. for minor).
 .sup.1 H-NMR (250 MHz, DMSO-d.sub.6): 12.75 (b.s., 1H, CO.sub.2 H); 11.28
 (s, "1H", mj., imide NH); 11.26 (s, "1H", mi., imide NH); 7.30 (s, "1H",
 mj., T H-6); 7.26 (s, "1H", mi., T H-6); 6.92 (b.t., "1H", mj., BOcNH);
 6.73 (b.t., "1H", mi., BOcNH); 4.64 (s, "2H", mj., CH.sub.2 CON); 4.46 (s,
 "2H", mj., CH.sub.2 CON); 4.19 (s, "2H", mi., CH.sub.2 CO.sub.2 H); 3.97
 (s, "2H", mj., CH.sub.2 CO.sub.2 H); 3.63-3.01 (unresolved m, includes
 water, CH.sub.2 CH.sub.2); 1.75 (s, 3H, CH.sub.3) and 1.38 (s, 9H, .sup.t
 Bu).
 EXAMPLE 39
 N.sup.4 -Benzyloxycarbonyl-1-(Boc-aeg)cytosine
 N'-Boc-aminoethyl glycine ethyl ester (5.00 g; 20.3 mmol), DhbtOH (3.64 g;
 22.3 mmol) and N.sup.4 -benzyloxycarbonyl-1-carboxymethyl cytosine (6.77
 g; 22.3 mmol) were suspended in DMF (100 ml). Methylene chloride (100 ml)
 then was added. The solution was cooled to 0.degree. C. and DCC (5.03 g;
 24.4 mmol) was added. The ice bath was removed after 2 h and stirring was
 continued for another hour at ambient temperature. The reaction mixture
 then was evaporated to dryness, in vacuo. The residue was suspended in
 ether (100 ml) and stirred vigorously for 30 min. The solid material was
 isolated by filtration and the ether wash procedure was repeated twice.
 The material was then stirred vigorously for 15 min with dilute sodium
 hydrogencarbonate (aprox. 4% solution, 100 ml), filtered and washed with
 water. This procedure was then repeated once, which after drying left 17.0
 g of yellowish solid material. The solid was then boiled with dioxane (200
 ml) and filtered while hot. After cooling, water (200 ml) was added. The
 precipitated material was isolated by filtration, washed with water, and
 dried. According to HPLC (observing at 260 nm) this material has a purity
 higher than 99%, besides the DCU. The ester was then suspended in THF (100
 ml), cooled to 0.degree. C., and 1 N LiOH (61 ml) was added. After
 stirring for 15 minutes, the mixture was filtered and the filtrate was
 washed with methylene chloride (2.times.150 ml). The alkaline solution
 then was cooled to 0.degree. C. and the pH was adjusted to 2.0 with 1 N
 HCl. The title compound was isolated by filtration and was washed once
 with water, leaving 11.3 g of a white powder after drying. The material
 was suspended in methylene chloride (300 ml) and petroleum ether (300 ml)
 was added. Filtration and wash afforded 7.1 g (69%) after drying. HPLC
 showed a purity of 99% R.sub.T =19.5 min, and a minor impurity at 12.6 min
 (approx. 1%) most likely the Z-de protected monomer. Anal. for C.sub.23
 H.sub.29 N.sub.5 O.sub.8 found(calc.) C: 54.16(54.87); H: 5.76(5.81) and
 N: 13.65(13.91). .sup.1 H-NMR (250 MHz, DMSO-d.sub.6). 10.78 (b.s, 1H,
 CO.sub.2 H); 7.88 (2 overlapping dublets, 1H, Cyt H-5); 7.41-7.32 (m, 5H,
 Ph); 7.01 (2 overlapping doublets, 1H, Cyt H-6); 6.94 & 6.78 (unres.
 triplets, 1H, BocNH); 5.19 (s, 2H, PhCH.sub.2); 4.81 & 4.62 (s, 2H,
 CH.sub.2 CON); 4.17 & 3.98 (s, 2H, CH.sub.2 CO.sub.2 H); 3.42-3.03 (m,
 includes water, CH.sub.2 CH.sub.2) and 1.38 & 1.37 (s, 9H, .sup.t Bu).
 .sup.13 C-NMR. 150.88; 128.52; 128.18; 127.96; 93.90; 66.53; 49.58 and
 28.22. IR: Frequency in cm.sup.-1 (intensity). 3423 (26.4), 3035 (53.2),
 2978(41.4), 1736(17.3), 1658(3.8), 1563(23.0), 1501(6.8) and 1456 (26.4).
 EXAMPLE 40
 9-Carboxymethyl adenine ethyl ester
 Adenine (10.0 g, 74 mmol) and potassium carbonate (10.29 g, 74.0 mmol) were
 suspended in DMF and ethyl bromoacetate (8.24 ml, 74 mmol) was added. The
 suspension was stirred for 2.5 h under nitrogen at room temperature and
 then filtered. The solid residue was washed three times with DMF (10 ml).
 The combined filtrate was evaporated to dryness, in vacuo. The
 yellow-orange solid material was poured into water (200 ml) and 4 N HCl
 was added to pH.apprxeq.6. After stirring at 0.degree. C. for 10 min, the
 solid was filtered off, washed with water, and recrystallized from 96%
 ethanol (150 ml). The title compound was isolated by filtration and washed
 thoroughly with ether. Yield 3.4 g (20%). M.p. 215.5-220.degree. C. Anal.
 for C.sub.9 H.sub.11 N.sub.5 O.sub.2 found(calc.): C: 48.86(48.65); H:
 5.01(4.91); N: 31.66(31.42). .sup.1 H-NMR (250 MHz; DMSO-d.sub.6): (s, 2H,
 H-2 & H-8), 7.25 (b. s., 2H, NH.sub.2), 5.06 (s, 2H, NCH.sub.2), 4.17 (q,
 2H, J=7.11 Hz, OCH.sub.2) and 1.21 (t, 3H, J=7.13 Hz, NCH.sub.2). .sup.13
 C-NMR. 152.70, 141.30, 61.41, 43.97 and 14.07. FAB-MS. 222 (MH+). IR:
 Frequency in cm.sup.-1 (intensity). 3855 (54.3), 3274(10.4), 3246(14.0),
 3117(5.3), 2989(22.3), 2940(33.9), 2876(43.4), 2753(49.0), 2346(56.1),
 2106(57.1), 1899(55.7), 1762(14.2), 1742(14.2), 1742(1.0), 1671(1.8),
 1644(10.9), 1606(0.6), 1582(7.1), 1522(43.8), 1477(7.2), 1445(35.8) and
 1422(8.6). The position of alkylation was verified by X-ray
 crystallography on crystals, which were obtained by recrystallization from
 96% ethanol.
 Alternatively, 9-carboxymethyl adenine ethyl ester can be prepared by the
 following procedure. To a suspension of adenine (50.0 g, 0.37 mol) in DMF
 (1100 ml) in 2 L three-necked flask equipped with a nitrogen inlet, a
 mechanical stirrer and a dropping funnel was added 16.4 g (0.407 mol)
 haxane washed sodium hydride-mineral oil dispersion. The mixture was
 stirred vigorously for 2 hours, whereafter ethy bromacetate 75 ml, 0.67
 mol) was added dropwise over the course of 3 hours. The mixture was
 stirred for one additional hour, whereafter tic indicated complete
 conversion of adenine. The mixture was evaporated to dryness at 1 mmHg and
 water (500 ml) was added to the oily residue which caused crystallisation
 of the title compound. The solid was recrystallised from 06% ethanol (600
 ml). Yield after drying 53.7 (65.6%). HPLC (215 nm) purity &gt;99.5%.
 EXAMPLE 41
 N.sup.6 -Benzyloxycarbonyl-9-carboxymethyl adenine ethyl ester
 9-Carboxymethyladenine ethyl ester (3.40 g, 15.4 mmol) was dissolved in dry
 DMF (50 ml) by gentle heating, cooled to 20.degree. C., and added to a
 solution of N-ethyl-benzyloxycarbonylimidazole tetrafluoroborate (62 mmol)
 in methylene chloride (50 ml) over a period of 15 min with ice-cooling.
 Some precipitation was observed. The ice bath was removed and the solution
 was stirred overnight. The reaction mixture was treated with saturated
 sodium hydrogen carbonate (100 ml). After stirring for 10 min, the phases
 were separated and the organic phase was washed successively with one
 volume of water, dilute potassium hydrogen sulfate (twice), and with
 saturated sodium chloride. The solution was dried over magnesium sulfate
 and evaporated to dryness, in vacuo, which afforded 11 g of an oily
 material. The material was dissolved in methylene chloride (25 ml), cooled
 to 0.degree. C., and precipitated with petroleumeum ether (50 ml). This
 procedure was repeated once to give 3.45 g (63%) of the title compound.
 M.p. 132-350.degree. C. Analysis for C.sub.17 H.sub.17 N.sub.5 O.sub.4
 found (calc.): C: 56.95(57.46); H: 4.71(4.82); N: 19.35(19.71). .sup.1
 H-NMR (250 MHz; CDCl.sub.3): 8.77 (s, 1H, H-2 or H-8); 7.99 (s, 1H, H-2 or
 H-8); 7.45-7.26 (m, 5H, Ph); 5.31 (s, 2H, N-CH.sub.2); 4.96 (s, 2H,
 Ph-CH.sub.2); 4.27 (q, 2H, J=7.15 Hz, CH.sub.2 CH.sub.3) and 1.30 (t, 3H,
 J=7.15 Hz, CH.sub.2 CH.sub.3). .sup.13 C-NMR: 153.09; 143.11; 128.66;
 67.84; 62.51; 44.24 and 14.09. FAB-MS: 356 (MH+) and 312 (MH+--CO.sub.2).
 IR: frequency in cm.sup.-1 (intensity). 3423 (52.1); 3182 (52.8);
 3115(52.1); 3031(47.9); 2981(38.6); 1747(1.1); 1617(4.8); 15.87(8.4);
 1552(25.2); 1511(45.2); 1492(37.9); 1465(14.0) and 1413(37.3).
 EXAMPLE 42
 N.sup.6 -Benzyloxycarbonyl-9-carboxymethyl adenine
 N.sup.6 -Benzyloxycarbonyl-9-carboxymethyladenine ethyl ester (3.20 g; 9.01
 mmol) was mixed with methanol (50 ml) cooled to 0.degree. C. Sodium
 Hydroxide Solution (50 ml; 2N) was added, whereby the material quickly
 dissolved. After 30 min at 0.degree. C., the alkaline solution was washed
 with methylene chloride (2.times.50ml). The aqueous solution was brought
 to pH 1.0 with 4 N HCl at 0.degree. C., whereby the title compound
 precipitated. The yield after filtration, washing with water, and drying
 was 3.08 g (104%). The product contained salt and elemental analysis
 reflected that. Anal. for C.sub.15 H.sub.13 N.sub.5 O.sub.4 found(calc.):
 C: 46.32(55.05); H: 4.24(4.00); N: 18.10(21.40) and C/N: 2.57(2.56).
 .sup.1 H-NMR(250 MHz; DMSO-d.sub.6): 8.70 (s, 2H, H-2 and H-8); 7.50-7.35
 (m, 5H, Ph); 5.27 (s, 2H, N-CH.sub.2); and 5.15 (s, 2H, Ph-CH.sub.2).
 .sup.13 C-NMR. 168.77, 152.54, 151.36, 148.75, 145.13, 128.51,
 128.17,127.98, 66.76 and 44.67.IR (KBr) 3484(18.3); 3109(15.9);
 3087(15.0); 2966(17.1); 2927(19.9); 2383(53.8); 1960(62.7); 1739(2.5);
 1688(5.2); 1655(0.9); 1594(11.7); 1560(12.3); 1530(26.3); 1499(30.5);
 1475(10.4); 1455(14.0); 1429(24.5) and 1411(23.6). FAB-MS: 328 (MH+) and
 284 (MH+--CO.sub.2). HPLC (215 nm, 260 nm) in system 1:15.18 min, minor
 impurities all less than 2%.
 EXAMPLE 43
 N.sup.6 -Benzyloxycarbonyl-1-(Boc-aeg)adenine ethyl ester
 N'-Boc-aminoethyl glycine ethyl ester (2.00 g; 8.12 mmol), DhbtOH (1.46 g;
 8.93 mmol) and N.sup.6 -benzyloxycarbonyl-9-carboxymethyl adenine (2.92 g;
 8.93 mmol) were dissolved in DMF (15 ml). Methylene chloride (15 ml) then
 was added. The solution was cooled to 0.degree. C. in an ethanol/ice bath.
 DCC (2.01 g; 9.74 mmol) was added. The ice bath was removed after 2.5 h
 and stirring was continued for another 1.5 hour at ambient temperature.
 The precipitated DCU was removed by filtration and washed once with DMF
 (15 ml), and twice with methylene chloride (2.times.15 ml). To the
 combined filtrate was added more methylene chloride (100 ml). The solution
 was washed successively with dilute sodium hydrogen carbonate (2.times.100
 ml), dilute potassium hydrogen sulfate (2.times.100 ml), and saturated
 sodium chloride (1.times.100 ml). The organic phase was evaporated to
 dryness, in vacuo, which afforded 3.28 g (73%) of a yellowish oily
 substance. HPLC of the raw product showed a purity of only 66% with
 several impurities, both more and less polar than the main peak. The oil
 was dissolved in absolute ethanol (50 ml) and activated carbon was added.
 After stirring for 5 minutes, the solution was filtered. The filtrate was
 mixed with water (30 ml) and was left with stirring overnight. The next
 day, the white precipitate was removed by filtration, washed with water,
 and dried, affording 1.16 g (26%) of a material with a purity higher than
 98% by HPLC. Addition of water to the mother liquor afforded another 0.53
 g with a purity of approx. 95%. Anal. for C.sub.26 H.sub.33 N.sub.7
 O.sub.7.degree.H.sub.2 O found(calc.) C: 55.01(54.44; H: 6.85(6.15) and N:
 16.47(17.09). .sup.1 H-NMR (250 MHz, CDCl.sub.3) 8.74 (s, 1H, Ade H-2);
 8.18 (b. s, 1H, ZNH); 8.10 & 8.04 (s, 1H, H-8); 7.46-7.34 (m, 5H, Ph);
 5.63 (unres. t, 1H, BocNH); 5.30 (s, 2H, PhCH.sub.2); 5.16 & 5.00 (s, 2H,
 CH.sub.2 CON); 4.29 & 4.06 (s, 2H, CHCO.sub.2 H); 4.20 (q, 2H, OCH.sub.2
 CH.sub.3); 3.67-3.29 (m, 4H, CH.sub.2 CH.sub.2); 1.42 (s, 9H, .sup.t Bu)
 and 1.27 (t, 3H, OCH.sub.2 CH.sub.3). The spectrum shows traces of ethanol
 and DCU.
 EXAMPLE 44
 N.sup.6 -Benzyloxycarbonyl-1-(Boc-aeg)adenine
 N.sup.6 -Benzyloxycarbonyl-1-(Boc-aeg)adenine ethyl ester (1.48 g; 2.66
 mmol) was suspended in THF (13 ml) and the mixture was cooled to 0.degree.
 C. Lithium hydroxide (8 ml; 1 N) was added. After 15 min of stirring, the
 reaction mixture was filtered, extra water (25 ml) was added, and the
 solution was washed with methylene chloride (2.times.25 ml). The pH of the
 aqueous solution was adjusted to pH 2.0 with 1 N HCl. The precipitate was
 isolated by filtration, washed with water, and dried, and drief affording
 0.82 g (58%). The product reprecipitated twice with methylene
 chloride/petroleum ether, 0.77 g (55%) after drying. M.p. 119.degree. C.
 (decomp.) Anal. for C.sub.24 H.sub.29 N.sub.7 O.sub.7.degree.H.sub.2 O
 found(calc.) C: 53.32(52.84); H: 5.71(5.73); N: 17.68(17.97). FAB-MS.
 528.5 (MH+). .sup.1 H-NMR (250 MHz, DMSO-d.sub.6). 12.75 (very b, 1H,
 CO.sub.2 H); 10.65 (b. s, 1H, ZNH); 8.59 (d, 1H, J=2.14 Hz, Ade H-2); 8.31
 (s, 1H, Ade H-8); 7.49-7.31 (m, 5H, Ph); 7.03 & 6.75 (unresol. t, 1H,
 BocNH); 5.33 & 5.16 (s, 2H, CH.sub.2 CON); 5.22 (s, 2H, PhCH.sub.2);
 4.34-3.99 (s, 2H, CH.sub.2 CO.sub.2 H); 3.54-3.03 (m's, includes water,
 CH.sub.2 CH.sub.2) and 1.39 & 1.37 (s, 9H, .sup.t Bu). .sup.13 C-NMR.
 170.4; 166.6; 152.3; 151.5; 149.5; 145.2; 128.5; 128.0; 127.9; 66.32;
 47.63; 47.03; 43.87 and 28.24.
 EXAMPLE 45
 2-Amino-6-chloro-9-carboxymethylpurine
 To a suspension of 2-amino-6-chloropurine (5.02 g; 29.6 mmol) and potassium
 carbonate (12.91 g; 93.5 mmol) in DMF (50 ml) was added bromoacetic acid
 (4.70 g; 22.8 mmol). The mixture was stirred vigorously for 20 h. under
 nitrogen. Water (150 ml) was added and the solution was filtered through
 Celite to give a clear yellow solution. The solution was acidified to a pH
 of 3 with 4 N hydrochloric acid. The precipitate was filtered and dried,
 in vacuo, over sicapent. Yield (3.02 g; 44.8%). .sup.1 H-NMR(DMSO-d6):
 d=4.88 ppm (s,2H); 6.95 (s,2H); 8.10 (s,1H).
 EXAMPLE 46
 2-Amino-6-benzyloxy-9-carboxymethylpurine
 Sodium (2.0 g; 87.0 mmol) was dissolved in benzyl alcohol (20 ml) and
 heated to 130.degree. C. for 2 h. After cooling to 0.degree. C., a
 solution of 2-amino-6-chloro-9-carboxymethylpurine (4.05 g; 18.0 mmol) in
 DMF (85 ml) was slowly added, and the resulting suspension stirred
 overnight at 20.degree. C. Sodium hydroxide solution (1N, 100 ml) was
 added and the clear solution was washed with ethyl acetate (3.times.100
 ml). The water phase then was acidified to a pH of 3 with 4 N hydrochloric
 acid. The precipitate was taken up in ethyl acetate (200 ml), and the
 water phase was extracted with ethyl acetate (2.times.100 ml). The
 combined organic phases were washed with saturated sodium chloride
 solution (2.times.75 ml), dried with anhydrous sodium sulfate, and taken
 to dryness by evaporation, in vacuo. The residue was recrystallized from
 ethanol (300 ml). Yield after drying, in vacou, over sicapent: 2.76 g
 (52%). M.p. 159-65.degree. C. Anal. (calc., found) C(56.18; 55.97),
 H(4.38; 4.32), N(23.4; 23.10). .sup.1 H-NMR (DMSO-d.sub.6): 4.82
 ppm.(s,2H); 5.51 (s,2H); 6.45 (s,2H); 7.45 (m,5H); 7.82 (s,1H).
 EXAMPLE 47
 N-([2-Amino-6-benzyloxy-purine-9-yl]-acetyl)-N-(2-Boc-aminoethyl)-glycine
 [BocGaeg-OH monomer].
 2-Amino-6-benzyloxy-9-carboxymethyl-purine (0.50 g; 1.67 mmol),
 methyl-N(2-[tert-butoxycarbonylamino]ethyl)glycinate (0.65 g; 2.80 mmol),
 diisopropylethyl amine (0.54 g; 4.19 mmol), and
 bromo-tris-pyrrolidino-phosphonium-hexafluoro-phosphate (PyBroP.RTM.)
 (0.798 g; 1.71 mmol) were stirred in DMF (2 ml) for 4 h. The clear
 solution was poured into an ice-cooled solution of sodium hydrogen
 carbonate (1 N; 40 ml) and extracted with ethyl acetate (3.times.40 ml).
 The organic layer was washed with potassium hydrogen sulfate solution (1
 N; 2.times.40 ml), sodium hydrogen carbonate (1 N; 1.times.40 ml) and
 saturated sodium chloride solution (60 ml). After drying with anhydrous
 sodium sulfate and evaporation, in vacuo, the solid residue was
 recrystallized from ethyl acetate/hexane (20 ml (2:1)) to give the methyl
 ester in 63% yield (MS-FAB 514 (M+1). Hydrolysis was accomplished by
 dissolving the ester in ethanol/water (30 ml (1:2)) containing conc.
 sodium hydroxide (1 ml). After stirring for 2 h, the solution was filtered
 and acidified to a pH of 3, by the addition of 4 N hydrochloric acid. The
 title compound was obtained by filtration. Yield: 370 mg (72% for the
 hydrolysis). Purity by HPLC was more than 99%. Due to the limited rotation
 around the secondary amide several of the signals were doubled in the
 ratio 2:1 (indicated in the list by mj. for major and mi. for minor).
 .sup.1 H-NMR(250, MHz, DMSO-d.sub.6): d=1.4 ppm. (s,9H); 3.2 (m,2H); 3.6
 (m,2H); 4.1 (s, mj., CONRCH.sub.2 COOH); 4.4 (s, mi., CONRCH.sub.2 COOH);
 5.0 (s, mi., Gua-CH.sub.2 CO--); 5.2 (s, mj., Gua-CH.sub.2 CO); 5.6
 (s,2H); 6.5 (s,2H); 6.9 (m, mi., BOcNH); 7.1 (m, mj., BOcNH); 7.5 (m.,3H);
 7.8 (s,1H); 12,8 (s; 1H). .sup.13 C-NMR. 170.95; 170.52; 167.29; 166.85;
 160.03; 159.78; 155.84; 154.87; 140.63; 136.76; 128.49; 128.10; 113.04;
 78.19; 77.86; 66.95; 49.22; 47.70; 46.94; 45.96; 43.62; 43.31 and 28.25.
 EXAMPLE 48
 3-Boc-amino-1,2-propanediol
 3-Amino-1,2-propanediol (40.00 g, 0.440 mol, 1.0 eq.) was dissolved in
 water (1000 ml) and cooled to 0.degree. C. Di-tert-butyl dicarbonate
 (115.0 g, 0.526 mol, 1.2 eq.) was added in one portion. The reaction
 mixture was heated to room temperature on a water bath during stirring.
 The pH was maintained at 10.5 with a solution of sodium hydroxide (17.56
 g, 0.440 mol, 1.0 eq.) in water (120 ml). When the addition of aqueous
 sodium hydroxide was completed, the reaction mixture was stirred overnight
 at room temperature. Subsequently, ethyl acetate (750 ml) was added to the
 reaction mixture, followed by cooling to 0.degree. C. The pH was adjusted
 to 2.5 with 4 N sulphuric acid with vigorous stirring. The phases were
 separated and the water phase was washed with additional ethyl acetate
 (6.times.350 ml). The volume of the organic phase was reduced to 900 ml by
 evaporation under reduced pressure. The organic phase then was washed with
 a saturated aqueous solution of potassium hydrogen sulfate diluted to
 twice its volume (1.times.1000 ml) and with saturated aqueous sodium
 chloride (1.times.500 ml). The organic phase was dried (MgSO.sub.4) and
 evaporated under reduced pressure to yield 50.12 g (60%) of the title
 compound. The product could be solidified by evaporation from methylene
 chloride and subsequent freezing. .sup.1 H-NMR (CDCl.sub.3 /TMS): d=1.43
 (s, 9H, Me.sub.3 C), 3.25 (m, 2H, CH.sub.2), 3.57 (m, 2H, CH.sub.2), 3.73
 (m, 1H, CH). .sup.13 C-NMR (CDCl.sub.3 /TMS): d=28.2 (Me.sub.3 C), 42.6
 (CH.sub.2), 63.5, 71.1 (CH.sub.2 OH, CHOH), 79.5 (Me.sub.3 C), 157.0
 (C.dbd.O).
 EXAMPLE 49
 2-(Boc-amino)ethyl-L-alanine methyl ester
 3-Boc-amino-1,2-propanediol (20.76 g, 0.109 mol, 1 eq.) was suspended in
 water (150 ml). Potassium m-periodate (24.97 g, 0.109 mol, 1 eq.) was
 added and the reaction mixture was stirred for 2 h at room temperature
 under nitrogen. The reaction mixture was filtered and the water phase
 extracted with chloroform (6.times.250 ml) The organic phase was dried
 (MgSO.sub.4) and evaporated to afford an almost quantitative yield of
 Boc-aminoacetaldehyde as a colourless oil, which was used without further
 purification in the following procedure.
 Palladium-on-carbon (10%, 0.8 g) was added to MeOH (250 ml) under nitrogen
 with cooling (0.degree. C.) and vigorous stirring. Anhydrous sodium
 acetate (4.49 g, 54.7 mmol, 2 eqv) and L-alanine methyl ester,
 hydrochloride (3.82 g, 27.4 mmol, 1 eqv) were added. Boc-aminoacetaldehyde
 (4.79 g, 30.1 mmol, 1.1 eqv) was dissolved in MeOH (150 ml) and added to
 the reaction mixture. The reaction mixture was hydrogenated at atmospheric
 pressure and room temperature until hydrogen uptake had ceased. The
 reaction mixture was filtered through celite, which was washed with
 additional MeOH. The MeOH was removed under reduced pressure. The residue
 was suspended in water (150 ml) and pH adjusted to 8.0 by dropwise
 addition of 0.5 N NaOH with vigorous stirring. The water phase was
 extracted with methylene chloride (4.times.250 ml). The organic phase was
 dried (MgSO.sub.4), filtered through celite, and evaporated under reduced
 pressure to yield 6.36 g (94%) of the title compound as a clear, slightly
 yellow oil. MS (FAB-MS): m/z (%)=247 (100, M+1, 191 (90), 147 (18). .sup.1
 H-NMR (250 MHz, CDCl.sub.3). 1.18 (d, J=7.0 Hz, 3H, Me), 1.36 (s, 9H,
 Me.sub.3 C), 1.89 (b, 1H, NH), 2.51 (m, 1H, CH.sub.2), 2.66 (m, 1H,
 CH.sub.2), 3.10 (m, 2H, CH.sub.2), 3.27 (q, J=7.0 Hz, 1H, CH), 3.64 (s,
 3H, OMe), 5.06 (b, 1H, carbamate NH). .sup.13 C-NMR. d=18.8 (Me), 28.2
 (Me.sub.3 C), 40.1, 47.0 (CH.sub.2), 51.6 (OMe), 56.0 (CH), 155.8
 (carbamate C.dbd.O), 175.8 (ester C.dbd.O).
 EXAMPLE 50
 N-(Boc-aminoethyl)-N-(1-thyminylacetyl)-L-alanine methyl ester
 To a solution of Boc-aminoethyl-(L)-alanine methyl ester (1.23 g, 5.0 mmol)
 in DMF (10 ml) was added Dhbt-OH (0.90 g, 5.52 mmol) and 1-thyminylacetic
 acid (1.01 g, 5.48 mmol). When the 1-thyminylacetic acid was dissolved,
 dichloromethane (10 ml) was added and the solution was cooled on an ice
 bath. After the reaction mixture had reached 0.degree. C., DCC (1.24 g,
 6.01 mmol) was added. Within 5 min after the addition, a precipitate of
 DCU was seen. After a further 5 min, the ice bath was removed. Two hours
 later, TLC analysis showed the reaction to be finished. The mixture was
 filtered and the precipitate washed with dichloromethane (100 ml). The
 resulting solution was extracted twice with 5% sodium hydrogen carbonate
 (150 ml) and twice with saturated potassium hydrogen sulfate (25 ml) in
 water (100 ml). After a final extraction with saturated sodium chloride
 (150 ml), the solution was dried with magnesium sulfate and evaporated to
 give a white foam. The foam was purified by column chromatography on
 silica gel using dichloromethane with a methanol gradient as eluent. This
 yielded a pure compound (&gt;99% by HPLC) (1.08 g, 52.4%) FAB-MS: 413 (M+1)
 and 431 (M+1+water). .sup.1 H-NMR (CDCl.sub.3): 4.52 (s, 2 H, CH'.sub.2);
 3.73 (s, 3 H, OMe); 3.2-3.6 (m, 4 H, ethyl CH.sub.2 's); 1.90 (s, 3 H, Me
 in T); 1.49 (d, 3 H, Me in Ala, J=7.3 Hz); 1.44 (s, 9 H, Boc).
 EXAMPLE 51
 N-(Boc-aminoethyl)-N-(1-thyminylacetyl)-L-alanine
 The methyl ester of the title compound (2.07 g, 5.02 mmol) was dissolved in
 methanol (100 ml), and cooled on an ice bath. 2 M sodium hydroxide (100
 ml) was added. After stirring for 10 min, the pH of the mixture was
 adjusted to 3 with 4 M hydrogen chloride. The solution was subsequently
 extracted with ethyl acetate (3.times.100 ml). The combined organic
 extracts were dried over magnesium sulfate. After evaporation, the
 resulting foam was dissolved in ethyl acetate (400 ml) and a few ml of
 methanol to dissolve the solid material. Petroleum ether then was added
 until precipitation started. After standing overnight at -20.degree. C.,
 the precipitate was removed by filtration. This gave 1.01 g (50.5%) of
 pure compound (&gt;99% by HPLC). The compound can be recrystallized from
 2-propanol. FAB-MS: 399 (M+1). .sup.1 H-NMR (DMSO-d.sub.6): 11.35 (s, 1 H,
 COO); 7.42 (s, 1 H, H'.sub.6); 4.69 (s, 2 H, CH'.sub.2); 1.83 (s, 3 H, Me
 in T); 1.50-1.40 (m, 12 H, Me in Ala+Boc).
 EXAMPLE 52
 (a) N-(Boc-aminoethyl)-N-(1-thyminylacetyl)-D-alanine methyl ester
 To a solution of Boc-aminoethyl alanine methyl ester (2.48 g, 10.1 mmol) in
 DMF (20 ml) was added Dhbt-OH (1.80 g, 11.0 mmol) and thyminylacetic acid
 (2.14 g, 11.6 mmol). After dissolution of the 1-thyminylacetic acid,
 methylene chloride (20 ml) was added and the solution cooled on an ice
 bath. When the reaction mixture had reached 0.degree. C., DCC (2.88 g,
 14.0 mmol) was added. Within 5 min after the addition a precipitate of DCU
 was seen. After 35 min the ice bath was removed. The reaction mixture was
 filtered 3.5 h later and the precipitate washed with methylene chloride
 (200 ml). The resulting solution was extracted twice with 5% sodium
 hydrogen carbonate (200 ml) and twice with saturated potassium hydrogen
 sulfate in water (100 ml). After a final extraction with saturated sodium
 chloride (250 ml), the solution was dried with magnesium sulfate and
 evaporated to give an oil. The oil was purified by short column silica gel
 chromatography using methylene chloride with a methanol gradient as
 eluent. This yielded a compound which was 96% pure according to HPLC (1.05
 g, 25.3%) after precipitation with petroleum ether. FAB-MS: 413 (M+1).
 .sup.1 H-NMR (CDCl.sub.3): 5.64 (t, 1 H, BocNH, J=5.89 Hz); 4.56 (d, 2 H,
 CH'.sub.2); 4.35 (q, 1 H, CH in Ala, J=7.25 Hz); 3.74 (s, 3 H, OMe);
 3.64-3.27 (m, 4 H, ethyl H's); 1.90 (s, 3 H, Me in T); 1.52-1.44 (t, 12 H,
 Boc+Me in Ala).
 (b) N-(Boc-aminoethyl)-N-(1-thyminylacetyl)-D-alanine
 The methyl ester of the title compound (1.57 g, 3.81 mmol) was dissolved in
 methanol (100 ml) and cooled on an ice bath. Sodium hydroxide (100 ml; 2
 M) was added. After stirring for 10 min the pH of the mixture was adjusted
 to 3 with 4 M hydrogen chloride. The solution then was extracted with
 ethyl acetate (3.times.100 ml). The combined organic extracts were dried
 over magnesium sulfate. After evaporation, the oil was dissolved in ethyl
 acetate (200 ml). Petroleum ether was added (to a total volume of 600 ml)
 until precipitation started. After standing overnight at -20.degree. C.,
 the precipitate was removed by filtration. This afforded 1.02 g (67.3%) of
 the title compound, which was 94% pure according to HPLC. FAB-MS: 399
 (M+1). .sup.1 H-NMR: 11.34 (s, 1 H, COOH); 7.42 (s, 1 H, H'.sub.6); 4.69
 (s, 2 H, CH'.sub.2); 4.40 (q, 1 H, CH in Ala, J=7.20 Hz); 1.83 (s, 3 H, Me
 in T); 1.52-1.40 (m, 12 H, Boc+Me in Ala).
 EXAMPLE 53
 N-(N'-Boc-3'-aminopropyl)-N-[(1-thyminyl)acetyl]glycine methyl ester
 N-(N'-Boc-3'-aminopropyl)glycine methyl ester (2.84 g, 0.0115 mol) was
 dissolved in DMF (35 ml), followed by addition of DhbtOH (2.07 g, 0.0127
 mol) and 1-thyminylacetic acid (2.34 g, 0.0127 mol). Methylene chloride
 (35 ml) was added and the mixture cooled to 0.degree. C. on an ice bath.
 After addition of DCC (2.85 g, 0.0138 mol), the mixture was stirred at
 0.degree. C. for 2 h, followed by 1 h at room temperature. The
 precipitated DCU was removed by filtration, washed with methylene chloride
 (25 ml), and a further amount of methylene chloride (150 ml) was added to
 the filtrate. The organic phase was extracted with sodium hydrogen
 carbonate (1 volume saturated diluted with 1 volume water, 6.times.250
 ml), potassium sulfate (1 volume saturated diluted with 4 volumes water,
 3.times.250 ml), and saturated aqueous sodium chloride (1.times.250 ml),
 dried over magnesium sulfate, and evaporated to dryness, in vacuo. The
 solid residue was suspended in methylene chloride (35 ml) and stirred for
 1 h. The precipitated DCU was removed by filtration and washed with
 methylene chloride (25 ml). The filtrate was evaporated to dryness, in
 vacuo, and the residue purified by column chromatography on silica gel,
 eluting with a mixture of methanol and methylene chloride (gradient from
 3-7% methanol in methylene chloride). This afforded the title compound as
 a white solid (3.05 g, 64%). M.p. 76-79.degree. C. (decomp.). Anal. for
 C.sub.18 H.sub.28 N.sub.4 O.sub.7, found (calc.) C: 52.03 (52.42) H: 6.90
 (6.84) N: 13.21 (13.58). The compound showed satisfactory .sup.1 H and
 .sup.13 C-NMR spectra.
 EXAMPLE 54
 N-(N'-Boc-3'-aminopropyl)-N-[(1-thyminyl)acetyl]glycine
 N-(N'-Boc-3'-aminopropyl)-N-[(1-thyminyl)acetyl]glycine methyl ester (3.02
 g, 0.00732 mol) was dissolved in methanol (25 ml) and stirred for 1.5 h
 with 2 M sodium hydroxide (25 ml). The methanol was removed by
 evaporation, in vacuo, and pH adjusted to 2 with 4 M hydrochloric acid at
 0.degree. C. The product was isolated as white crystals by filtration,
 washed with water (3.times.10 ml), and dried over sicapent, in vacuo.
 Yield 2.19 g (75%). Anal. for C.sub.17 H.sub.26 N.sub.4 O.sub.7, H.sub.2
 O, found (calc.) C: 49.95 (49.03) H: 6.47 (6.29) N: 13.43 (13.45). The
 compound showed satisfactory .sup.1 H and .sup.13 C-NMR spectra.
 EXAMPLE 55
 3-(1-Thyminyl)-propanoic acid methyl ester
 Thymine (14.0 g, 0.11 mol) was suspended in methanol. Methyl acrylate (39.6
 ml, 0.44 mol) was added, along with catalytic amounts of sodium hydroxide.
 The solution was refluxed in the dark for 45 h, evaporated to dryness, in
 vacuo, and the residue dissolved in methanol (8 ml) with heating. After
 cooling on an ice bath, the product was precipitated by addition of ether
 (20 ml), isolated by filtration, washed with ether (3.times.15 ml), and
 dried over sicapent, in vacuo. Yield 11.23 g (48%). M.p. 112-119.degree.
 C. Anal. for C.sub.9 H.sub.12 N.sub.2 O.sub.4, found (calc.) C: 51.14
 (50.94) H: 5.78 (5.70) N: 11.52 (13.20). The compound showed satisfactory
 .sup.1 H and .sup.13 C-NMR spectra.
 EXAMPLE 56
 3-(1-Thyminyl)-propanoic acid
 3-(1-Thyminyl)-propanoic acid methyl ester (1.0 g, 0.0047 mol) was
 suspended in 2 M sodium hydroxide (15 ml), boiled for 10 min. The pH was
 adjusted to 0.3 with conc. hydrochloric acid. The solution was extracted
 with ethyl acetate (10.times.25 ml). The organic phase was extracted with
 saturated aqueous sodium chloride, dried over magnesium sulfate, and
 evaporated to dryness, in vacuo, to give the title compound as a white
 solid (0.66 g, 71%). M.p. 118-121.degree. C. Anal. for C.sub.8 H.sub.10
 N.sub.2 O.sub.4, found (calc.) C: 48.38 (48.49) H: 5.09 (5.09) N: 13.93
 (14.14). The compound showed satisfactory .sup.1 H and .sup.13 C-NMR
 spectra.
 EXAMPLE 57
 N-(N'-Boc-aminoethyl)-N-[(1-thyminyl)propanoyl]glycine ethyl ester
 N-(N'-Boc-aminoethyl)glycine ethyl ester (1.0 g, 0.0041 mol) was dissolved
 in DMF (12 ml). DhbtOH (0.73 g, 0.0045 mol) and 3-(1-thyminyl)-propanoic
 acid (0.89 g, 0.0045 mol) were added. Methylene chloride (12 ml) then was
 added and the mixture was cooled to 0.degree. C. on an ice bath. After
 addition of DCC (1.01 g, 0.0049 mol), the mixture was stirred at 0.degree.
 C. for 2 h, followed by 1 h at room temperature. The precipitated DCU was
 removed by filtration, washed with methylene chloride (25 ml), and a
 further amount of methylene chloride (50 ml) was added to the filtrate.
 The organic phase was extracted with sodium hydrogen carbonate (1 volume
 saturated diluted with 1 volume water, 6.times.100 ml), potassium sulfate
 (1 volume saturated diluted with 4 volumes water, 3.times.100 ml), and
 saturated aqueous sodium chloride (1.times.100 ml), dried over magnesium
 sulfate, and evaporated to dryness, in vacuo. The solid residue was
 suspended in methylene chloride (15 ml), and stirred for 1 h. The
 precipitated DCU was removed by filtration and washed with methylene
 chloride. The filtrate was evaporated to dryness, in vacuo, and the
 residue purified by column chromatography on silica gel, eluting with a
 mixture of methanol and methylene chloride (gradient from 1 to 6% methanol
 in methylene chloride). This afforded the title compound as a white solid
 (1.02 g, 59%). Anal. for C.sub.19 H.sub.30 N.sub.4 O.sub.7, found (calc.)
 C: 53.15 (53.51) H: 6.90 (7.09) N: 12.76 (13.13). The compound showed
 satisfactory .sup.1 H and .sup.13 C-NMR spectra.
 EXAMPLE 58
 N-(N'-Boc-aminoethyl)-N-[(1-thyminyl)propanoyl]glycine
 N-(N'-Boc-aminoethyl)-N-[(1-thyminyl)propanoyl]glycine ethyl ester (0.83 g,
 0.00195 mol) was dissolved in methanol (25 ml). Sodium hydroxide (25 ml; 2
 M) was added. The solution was stirred for 1 h. The methanol was removed
 by evaporation, in vacuo, and the pH adjusted to 2 with 4 M hydrochloric
 acid at 0.degree. C. The product was isolated by filtration, washed with
 ether (3.times.15 ml), and dried over sicapent, in vacuo. Yield 0.769 g,
 99%). M.p. 213.degree. C. (de-comp.).
 EXAMPLE 59
 Mono-Boc-ethylenediamine (2).
 tert-Butyl-4-nitrophenyl carbonate (1) (10.0 g; 0.0418 mol) dissolved in
 DMF (50 ml) was added dropwise over a period of 30 min to a solution of
 ethylenediamine (27.9 ml; 0.418 mol) and DMF (50 ml) and stirred
 overnight. The mixture was evaporated to dryness, in vacuo, and the
 resulting oil dissolved in water (250 ml). After cooling to 0.degree. C.,
 pH was adjusted to 3.5 with 4 M hydrochloric acid. The solution then was
 filtered and extracted with chloroform (3.times.250 ml). The pH was
 adjusted to 12 at 0.degree. C. with 2 M sodium hydroxide, and the aqueous
 solution extracted with methylene chloride (3.times.300 ml). After
 treatment with sat. aqueous sodium chloride (250 ml), the methylene
 chloride solution was dried over magnesium sulfate. After filtration, the
 solution was evaporated to dryness, in vacuo, resulting in 4.22 g (63%) of
 the product (oil). .sup.1 H-NMR (90 MHz; CDCl.sub.3): .delta.1.44 (s, 9H);
 2.87 (t, 2H); 3.1 (q, 2H); 5.62 (s, broad)
 EXAMPLE 60
 (N-Boc-aminoethyl)-.beta.-alanine methyl ester, HCl
 Mono-Boc-ethylenediamine (2) (16.28 g; 0.102 mol) was dissolved in
 acetonitrile (400 ml) and methyl acrylate (91.50 ml; 1.02 mol) was
 transferred to the mixture with acetonitrile (200 ml). The solution was
 refluxed overnight under nitrogen in the dark to avoid polymerization of
 methyl acrylate. After evaporation to dryness, in vacuo, a mixture of
 water and ether (200+200 ml) was added, and the solution was filtered and
 vigorously stirred. The aqueous phase was extracted one more time with
 ether and then freeze dried to yield a yellow solid. Recrystallization
 from ethyl acetate yielded 13.09 g (46%) of the title compound. M.p.
 138-140.degree. C. Anal. for C.sub.11 H.sub.23 N.sub.2 O.sub.4 Cl, found
 (calc.) C: 46.49 (46.72) H: 8.38 (8.20) N: 9.83 (9.91) Cl: 12.45 (12.54).
 .sup.1 H-NMR (90 MHz; DMSO-d.sub.6): .delta. 1.39 (s, 9H); 2.9 (m, 8H);
 3.64 (s, 3H).
 EXAMPLE 61
 N-[(1-Thyminyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine methyl ester
 (N-Boc-amino-ethyl)-.beta.-alanine methyl ester, HCl (3) (2.0 g; 0.0071
 mol) and 1-thyminylacetic acid pentafluorophenyl ester (5) (2.828 g;
 0.00812 mol) were dissolved in DMF (50 ml). Triethyl amine (1.12 ml;
 0.00812 mol) was added and the mixture stirred overnight. After addition
 of methylene chloride (200 ml) the organic phase was extracted with
 aqueous sodium hydrogen carbonate (3.times.250 ml), half-sat. aqueous
 potassium hydrogen sulfate (3.times.250 ml), and sat. aqueous sodium
 chloride (250 ml) and dried over magnesium sulfate. Filtration and
 evaporation to dryness, in vacuo, resulted in 2.9 g (99%) yield (oil).
 .sup.1 H-NMR (250 MHz; CDCl.sub.3): due to limited rotation around the
 secondary amide several of the signals were doubled; .delta.1.43 (s, 9H);
 1.88 (s, 3H); 2.63 (t, 1H); 2.74 (t, 1H); 3.25-3.55 (4.times.t, 8H); 3.65
 (2.times.t, 2H); 3.66 (s, 1.5); 3.72 (s, 1.5); 4.61 (s, 1H); 4.72 (s, 2H);
 5.59 (s, 0.5H); 5.96 (s, 0.5H); 7.11 (s, 1H); 10.33 (s, 1H).
 EXAMPLE 62
 N-[(1-Thyminyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine
 N-[(1-Thyminyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine methyl ester (3.0
 g; 0.0073 mol) was dissolved in 2 M sodium hydroxide (30 ml), the pH
 adjusted to 2 at 0.degree. C. with 4 M hydrochloric acid, and the solution
 stirred for 2 h. The precipitate was isolated by filtration, washed three
 times with cold water, and dried over sicapent, in vacuo. Yield 2.23 g
 (77%). M.p. 170-176.degree. C. Anal. for C.sub.17 H.sub.26 N.sub.4
 O.sub.7, H.sub.2 O, found (calc.) C: 49.49 (49.03) H: 6.31 (6.78) N: 13.84
 (13.45). .sup.1 H-NMR (90 MHz; DMSO-d.sub.6): .delta.1.38 (s, 9H); 1.76
 (s, 3H); 2.44 and 3.29 (m, 8H); 4.55 (S, 2H); 7.3 (s, 1H); 11.23 (s, 1H).
 FAB-MS: 399 (M+1).
 EXAMPLE 63
 N-[(1-(N.sup.4 -Z)-cytosyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine methyl
 ester
 (N-Boc-amino-ethyl)-.beta.-alanine methyl ester, HCl (3) (2.0 g; 0.0071
 mol) and 1-(N-4-Z)-cytosylacetic acid pentafluorophenyl ester (5) (3.319
 g; 0.0071 mol) were dissolved in DMF (50 ml). Triethyl amine (0.99 ml;
 0.0071 mol) was added and the mixture stirred overnight. After addition of
 methylene chloride (200 ml), the organic phase was extracted with aqueous
 sodium hydrogen carbonate (3.times.250 ml), half-sat. aqueous potassium
 hydrogen sulfate (3.times.250 ml), and sat. aqueous sodium chloride (250
 ml), and dried over magnesium sulfate. Filtration and evaporation to
 dryness, in vacuo, resulted in 3.36 g of solid compound which was
 recrystallized from methanol. Yield 2.42 g (64%). M.p. 158-161.degree. C.
 Anal. for C.sub.25 H.sub.33 N.sub.5 O.sub.8, found (calc.) C: 55.19
 (56.49) H: 6.19 (6.26) N: 12.86 (13.18). .sup.1 H-NMR (250 MHz;
 CDCl.sub.3): due to limited rotation around the secondary amide several of
 the signals were doubled; .delta.1.43 (s, 9H); 2.57 (t, 1H); 3.60-3.23
 (m's, 6H); 3.60 (s, 1,5H); 3.66 (s, 1.5H); 4.80 (s, 1H); 4.88 (s, 1H);
 5.20 (s, 2H); 7.80-7.25 (m's, 7H). FAB-MS: 532 (M+1).
 EXAMPLE 64
 N-[(1-(N.sup.4 -Z) -cytosyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine
 N-[(1-(N-4-Z) -cytosyl)acetyl]-N'-Boc-aminoethyl-.beta.-alanine methyl
 ester (0.621 g; 0.0012 mol) was dissolved in 2 M sodium hydroxide (8.5 ml)
 and stirred for 2 h. Subsequently, pH was adjusted to 2 at 0.degree. C.
 with 4 M hydrochloric acid and the solution stirred for 2 h. The
 precipitate was isolated by filtration, washed three times with cold
 water, and dried over sicapent, in vacuo. Yield 0.326 g (54%). The white
 solid was recrystallized from 2-propanol and washed with petroleum ether.
 Mp.163.degree. C. (decomp.). Anal. for C.sub.24 H.sub.31 N.sub.5 O.sub.8,
 found (calc.) C: 49.49 (49.03) H: 6.31 (6.78) N: 13.84 (13.45). .sup.1
 H-NMR (250 MHz; CDCl.sub.3): due to limited rotation around the secondary
 amide several of the signals were doubled; .delta.1.40 (s, 9H); 2.57 (t,
 1H); 2.65 (t, 1H); 3.60-3.32 (m's, 6H); 4.85 (s, 1H); 4.98 (s, 1H); 5.21
 (s, 2H); 5.71 (s, 1H, broad); 7.99-7.25 (m's, 7H). FAB-MS: 518 (M+1).
 EXAMPLE 65
 Example of a PNA-Oligomer with a Guanine Residue
 (a) Solid-Phase Synthesis of H-[Taeg].sub.5 -[Gaeg]-[Taeg].sub.4
 -Lys-NH.sub.2
 The protected PNA was assembled onto a Boc-Lys(ClZ) modified MBHA resin
 with a substitution of approximately 0.15 mmol/g (determined by
 quantitative Ninhydrin reaction). Capping of uncoupled amino groups was
 only carried out before the incorporation of the BocGaeg-OH monomer.
 (b) Stepwise Assembly of H-[Taeg].sub.5 -[Gaeg]-[Taeg].sub.4 -Lys-NH.sub.2
 (Synthetic Protocol)
 Synthesis was initiated on 102 mg (dry weight) of preswollen (overnight in
 DCM) and neutralized Boc-Lys (ClZ)-MBHA resin. The steps performed were as
 follows: (1) Boc-deprotection with TFA/DCM (1:1, v/v), 1.times.2 min and
 1.times.1/2h, 3 ml; (2) washing with DCM, 4.times.20 sec, 3 ml; washing
 with DMF, 2.times.20 sec, 3 ml; washing with DCM, 2.times.20 sec, 3 ml,
 and drain for 30 sec; (3) neutralization with DIEA/DCM (1:19 v/v),
 2.times.3 min, 3 ml; (4) washing with DCM, 4.times.20 sec, 3 ml, and drain
 for 1 min.; (5) addition of 4 equiv. diisopropyl carbodiimide (0.06 mmol;
 9.7 .mu.l) and 4 equiv. (0.06 mmol; 24 mg) BocTaeg-OH or (0.06 mmol; 30
 mg) BocGaeg-OH dissolved in 0.6 ml DCM/DMF (1:1, v/v) (final concentration
 of monomer 0.1 M), the coupling reaction was allowed to proceed for 1/2 h
 shaking at room temperature; (6) drain for 20 sec; (7) washing with DMF,
 2.times.20 sec and 1.times.2 min, 3 ml; washing with DCM 4.times.20 sec, 3
 ml; (8) neutralization with DIEA/DCM (1:19 v/v), 2.times.3 min, 3 ml; (9)
 washing with DCM 4.times.20 sec, 3 ml, and drain for 1 min.; (10)
 qualitative Kaiser test; (11) blocking of unreacted amino groups by
 acetylation with Ac.sub.2 O/pyridine/DCM (1:1:2, v/v), 1.times.1/2 h, 3
 ml; and (12) washing with DCM, 4.times.20 sec, 2.times.2 min and
 2.times.20 sec. 3 ml. Steps 1-12 were repeated until the desired sequence
 was obtained. All qualitative Kaiser tests were negative (straw-yellow
 colour with no coloration of the beads) indicating near 100% coupling
 yield. The PNA-oligomer was cleaved and purified by the normal procedure.
 FAB-MS: 2832.11 [M*+1] (calc. 2832.15)
 EXAMPLE 66
 Solid-Phase Synthesis of H-Taeg-Aaeg-[Taeg].sub.8 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-Taeg-A(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-MBHA Resin
 About 0.3 g of wet Boc-[Taeg].sub.8 -Lys(ClZ)-MBHA resin was placed in a 3
 ml SPPS reaction vessel. Boc-Taeg-A(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-MBHA
 resin was assembled by in situ DCC coupling (single) of the A(Z)aeg
 residue utilizing 0.19 M of BocA(Z)aeg-OH together with 0.15 M DCC in 2.5
 ml 50% DMF/CH.sub.2 Cl.sub.2 and a single coupling with 0.15 M
 BocTaeg-OPfp in neat CH.sub.2 Cl.sub.2 ("Synthetic Protocol 5"). The
 synthesis was monitored by the quantitative ninhydrin reaction, which
 showed about 50% incorporation of A(Z)aeg and about 96% incorporation of
 Taeg.
 (b) Cleavage, Purification, and Identification of H-Taeg-Aaeg-[Taeg].sub.8
 -Lys-NH.sub.2
 The protected Boc-Taeg-A(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-BAH resin was treated
 as described in Example 27c to yield about 15.6 mg of crude material upon
 HF cleavage of 53.1 mg dry H-Taeg-A(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-BHA
 resin. The main peak at 14.4 min accounted for less than 50% of the total
 absorbance. A 0.5 mg portion of the crude product was purified to give
 approximately 0.1 mg of H-Taeg-Aaeg-[Taeg].sub.8 -Lys-NH.sub.2. For (MH+)*
 the calculated m/z value was 2816.16 and the measured m/z value was
 2816.28.
 (c) Synthetic Protocol 5
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 2.5 ml,
 3.times.1 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 2.5
 ml, 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2.5 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 2.5 ml,
 6.times.1 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin is
 taken out and dried thoroughly for a quantitative ninhydrin analysis to
 determine the substitution; (6) addition of 0.47 mmol (0.25 g)
 BocA(Z)aeg-OH dissolved in 1.25 ml DMF followed by addition of 0.47 mmol
 (0.1 g) DCC in 1.25 ml CH.sub.2 Cl.sub.2 or 0.36 mmol (0.20 g)
 BocTaeg-OPfp in 2.5 ml CH.sub.2 Cl.sub.2 ; the coupling reaction was
 allowed to proceed for a total of 20-24 hrs shaking; (7) washing with DMF,
 2.5 ml, 1.times.2 min; (8) washing with CH.sub.2 Cl.sub.2, 2.5 ml,
 4.times.1 min; (9) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2.5 ml, 2.times.2 min; (10) washing with CH.sub.2 Cl.sub.2, 2.5 ml,
 6.times.1 min; (11) 2-5 mg sample of protected PNA-resin is taken out and
 dried thoroughly for a quantitative ninhydrin analysis to determine the
 extent of coupling; (12) blocking of unreacted amino groups by acetylation
 with a 25 ml mixture of acetic anhydride/pyridine/CH.sub.2 Cl.sub.2
 (1:1:2, v/v/v) for 2 h (except after the last cycle); and (13) washing
 with CH.sub.2 Cl.sub.2, 2.5 ml, 6.times.1 min; (14) 2.times.2-5 mg samples
 of protected PNA-resin are taken out, neutralized with DIEA/CH.sub.2
 Cl.sub.2 (1: 19, v/v) and washed with CH.sub.2 Cl.sub.2 for ninhydrin
 analyses.
 EXAMPLE 67
 Solid-Phase Synthesis of H-[Taeg].sub.2 -Aaeg-[Taeg].sub.5 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.2 -A(Z)aeg-[Taeg].sub.5 -Lys (ClZ)
 -MBHA Resin
 About 0. 5 g of wet Boc-[Taeg].sub.5 -Lys(ClZ)-MBHA resin was placed in a 5
 ml SPPS reaction vessel. Boc-[Taeg].sub.2 -A(Z)aeg-[Taeg].sub.5
 -Lys(ClZ)-MBHA resin was assembled by in situ DCC coupling of both the
 A(Z)aeg and the Taeg residues utilising 0.15 M to 0.2 M of protected PNA
 monomer (free acid) together with an equivalent amount of DCC in 2 ml neat
 CH.sub.2 Cl.sub.2 ("Synthetic Protocol 6"). The synthesis was monitored by
 the quantitative ninhydrin reaction which showed a total of about 82%
 incorporation of A(Z)aeg after coupling three times (the first coupling
 gave about 50% incorporation; a fourth HOBt-mediated coupling in 50%
 DMF/CH2Cl2 did not increase the total coupling yield significantly) and
 quantitative incorporation (single couplings) of the Taeg residues.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.2 -Aaeg-
 [Taeg].sub.5 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.2 -A(Z)aeg-[Taeg].sub.5 -Lys(ClZ)-BHA resin
 was treated as described in Example 27c to yield about 16.2 mg of crude
 material upon HF cleavage of 102.5 mg dry H-[Taeg].sub.2
 -A(Z)aeg-[Taeg].sub.5 -Lys(ClZ)-BHA resin. A small portion of the crude
 product was purified. For (MH+)*, the calculated m/z value was 2050.85 and
 the measured m/z value was 2050.90
 (c) Synthetic Protocol 6
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v) , 2 ml,
 3.times.1 min and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 2
 ml, 6.times.1 min; (3) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2 ml, 3.times.2 min; (4) washing with CH.sub.2 Cl.sub.2, 2 ml,
 6.times.1 min, and drain for 1 min; (5) 2-5 mg sample of PNA-resin was
 taken out and dried thoroughly for a quantitative ninhydrin analysis to
 determine the substitution; (6) addition of 0.44 mmol (0.23 g)
 BocA(Z)aeg-OH dissolved in 1.5 ml CH.sub.2 Cl.sub.2 followed by addition
 of 0.44 mmol (0.09 g) DCC in 0.5 ml CH.sub.2 Cl.sub.2 or 0.33 mmol (0.13
 g) BocTaeg-OH in 1.5 ml CH.sub.2 Cl.sub.2 followed by addition of 0.33
 mmol (0.07 g) DCC in 0.5 ml CH.sub.2 Cl.sub.2; ; the coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking; (7) washing with
 DMF, 2 ml, 1.times.2 min; (8) washing with CH.sub.2 Cl.sub.2, 2 ml,
 4.times.1 min; (9) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2 ml, 2.times.2 min; (10) washing with CH.sub.2 Cl.sub.2, 2 ml,
 6.times.1 min; (11) 2-5 mg sample of protected PNA-resin is taken out and
 dried thoroughly for a quantitative ninhydrin analysis to determine the
 extent of coupling; (12) blocking of unreacted amino groups by acetylation
 with a 25 ml mixture of acetic anhydride/pyridine/CH.sub.2 Cl.sub.2
 (1:1:2, v/v/v) for 2 h (except after the last cycle); (13) washing with
 CH.sub.2 Cl.sub.2, 2 ml, 6.times.1 min; and (14) 2.times.2-5 mg samples of
 protected PNA-resin were taken out, neutralized with DIEA/CH.sub.2
 Cl.sub.2 (1: 19, v/v) and washed with CH.sub.2 Cl.sub.2 for ninhydrin
 analyses.
 EXAMPLE 68
 The PNA-oligomer H-T.sub.4 C.sub.2 TCTC-LysNH.sub.2 (SEQ ID NO:11) was
 prepared as described in Example 103. Hybridization experiments with this
 sequence should resolve the issue of orientation, since it is truly
 asymmetrical. Such experiments should also resolve the issues of
 pH-dependency of the Tm, and the stoichiometry of complexes formed.
 Hybridization experiments with the PNA-oligomer H-T.sub.4 C.sub.2
 TCTC-LysNH.sub.2 were performed as follows:

Row Hybridized With pH Tm .sctn.
 1 5'-(dA).sub.4 (dG).sub.2 (dA)(dG)(dA)(dG) 7.2 55.5 2:1
 2 5'-(dA).sub.4 (dG).sub.2 (dA)(dG)(dA)(dG) 9.0 26.0 2:1
 3 5'-(dA).sub.4 (dG).sub.2 (dA)(dG)(dA)(dG) 5.0 88.5 2:1
 4 5'-(dG)(dA)(dG)(dA)(dG).sub.2 (dA).sub.4 7.2 38.0 2:1
 5 5'-(dG)(dA)(dG)(dA)(dG).sub.2 (dA).sub.4 9.0 31.5 --
 6 5'-(dG)(dA)(dG)(dA)(dG).sub.2 (dA).sub.4 5.0 52.5 --
 7 5'-(dA).sub.4 (dG)(dT)(dA)(dG)(dA)(dG) 7.2 39.0 --
 8 5'-(dA).sub.4 (dG)(dT)(dA)(dG)(dA)(dG) 9.0 &lt;20 --
 9 5'-(dA).sub.4 (dG)(dT)(dA)(dG)(dA)(dG) 5.0 51.5 --
 10 5'-(dA).sub.4 (dG).sub.2 (dT)(dG)(dA)(dG) 7.2 31.5 --
 11 5'-(dA).sub.4 (dG).sub.2 (dT)(dG)(dA)(dG) 5.0 50.5 --
 12 5'-(dG)(dA)(dG)(dA)dT)(dG)(dA).sub.4 7.2 24.5 --
 13 5'-(dG)(dA)(dG)(dA)dT)(dG)(dA).sub.4 9.0 &lt;20 --
 14 5'-(dG)(dA)(dG)(dA)dT)(dG)(dA).sub.4 5.0 57.0 --
 15 5'-(dG)(dA)(dG)(dT)(dG).sub.2 (dA).sub.4 7.2 25.0 --
 16 5'-(dG)(dA)(dG)(dT)(dG).sub.2 (dA).sub.4 5.0 39.5 --
 52.0
 .sctn. = stoichiometry determined by UV-mixing curves
 -- = not determined
 These results show that a truly mixed sequence gave rise to well defined
 melting curves. The PNA-oligomers can actually bind in both orientations
 (compare row 1 and 4), although there is preference for the
 N-terminal/5'-orientation. Introducing a single mismatch opposite either T
 or C caused a lowering of T.sub.m by more than 16.degree. C. at pH 7.2; at
 pH 5.0 the T.sub.m -value was lowered more than 27.degree. C. This shows
 that there is a very high degree a sequence-selectivity which should be a
 general feature for all PNA C/T sequences.
 As indicated above, there is a very strong pH-dependency for the T.sub.m
 -value, indicating that Hoogsteen basepairing is important for the
 formation of hybrids. Therefore, it is not surprising that the
 stoichiometry was found to be 2:1.
 The lack of symmetry in the sequence and the very large lowering of T.sub.m
 when mismatches are present show that the Watson-Crick strand and the
 Hoogsteen strand are parallel when bound to complementary DNA. This is
 true for both of the orientations, i.e., 5'/N-terminal and 3'/N-terminal.
 EXAMPLE 69
 The results of hybridization experiments with H-T.sub.5 GT.sub.4
 -LysNH.sub.2 to were performed as follows:

Row Deoxyoligonucleotide Tm
 1 5'-(dA)5(dA)(dA)4-3' 55.0
 2 5'-(dA)5(dG)(dA)4-3' 47.0
 3 5'-(dA)5(dG)(dA)4-3' 56.5
 4 5'-(dA)5(dT)(dA)4-3' 46.5
 5 5'-(dA)4(dG)(dA)5-3' 48.5
 6 5'-(dA)4(dC)(dA)5-3' 55.5
 7 5'-(dA)4(dT)(dA)5-3' 47.0
 As shown by comparing rows 1, 3, and 6 with rows 2, 4, 5, and 7, G can in
 this mode discriminate between C/A and G/T in the DNA-strand, i.e.,
 sequence discrimination is observed. The complex in row 3 was furthermore
 determined to be 2 PNA: 1 DNA complex by UV-mixing curves.
 EXAMPLE 70
 The masses of some synthesized PNA-oligomers, as determined by FAB mass
 spectrometry, are as follows:

PNA DNA T.sub.m
 H-T.sub.10 -LysNH.sub.2 (dA).sub.10 73.degree. C.
 H-T.sub.4 (Ac)T.sub.5 -LysNH.sub.2 (dA).sub.10 49.degree. C.
 H-T.sub.4 (AC)T.sub.5 -LysNH.sub.2 (dA).sub.4 (dG)(dA).sup.5
 37.degree. C.
 H-T.sub.4 (Ac)T.sub.5 -LysNH.sub.2 (dA).sub.4 (dC)(dA).sup.5
 41.degree. C.
 H-T.sub.4 (AC)T.sub.5 -LysNH.sub.2 (dA).sub.4 (dT)(dA).sup.5
 41.degree. C.
 H-T.sub.4 (AC)T.sub.5 -LysNH.sub.2 (dA).sub.5 (dG)(dA).sup.4
 36.degree. C.
 H-T.sub.4 (AC)T.sub.5 -LysNH.sub.2 (dA).sub.5 (dC)(dA).sup.4
 40.degree. C.
 H-T.sub.4 (AC)T.sub.5 -LysNH.sub.2 (dA).sub.5 (dT)(dA).sup.4
 40.degree. C.
 EXAMPLE 73
 lodination Procedure
 A 5 .mu.g portion of Tyr-PNA-T.sub.10 -Lys-NH.sub.2 is dissolved in 40
 .mu.l 100 mM Na-phosphate, pH 7.0, and 1 mCi Na.sup.125 I and 2 .mu.l
 chloramine-T (50 mM in CH.sub.3 CN) are added. The solution is left at
 20.degree. C. for 10 min and then passed through a 0.5+5 cm Sephadex G10
 column. The first 2 fractions (100 .mu.l each) containing radioactivity
 are collected and purified by HPLC: reversed phase C-18 using a 0-60%
 CH.sub.3 CN gradient in 0.1% CF.sub.3 COOH in H.sub.2 O. The .sup.125
 I-PNA elutes right after the PNA peak. The solvent is removed under
 reduced pressure.
 EXAMPLE 74
 Binding of PNAs-T.sub.10 /T.sub.9 C/T.sub.8 C.sub.2 to Double Stranded DNA
 Targets A.sub.10 /A.sub.9 G/A.sub.8 G.sub.2 (FIG. 13)
 A mixture of 200 cps .sup.32 P-labeled EcoRI-PvuII fragment (the large
 fragment labeled at the 3'-end of the EcoRI site) of the indicated
 plasmid, 0.5 .mu.g carrier calf thymus DNA, and 300 ng PNA in 100 .mu.l
 buffer (200 mM NaCl, 50 mM Na-acetate, pH 4.5, 1 mM ZnSO.sub.4) was
 incubated at 37.degree. C. for 120 min. A 50 unit portion of nuclease
 S.sub.1 was added and incubated at 20.degree. C. for 5 min. The reaction
 was stopped by addition of 3 .mu.l 0.5 M EDTA and the DNA was precipitated
 by addition of 250 .mu.l 2% potassium acetate in ethanol. The DNA was
 analyzed by electrophoresis in 10% polyacrylamide sequencing gels and the
 radiolabeled DNA bands visualized by autoradiography.
 The target plasmids were prepared by cloning of the appropriate
 oligonucleotides into pUC19. Target A.sub.10 : oligonucleotides
 GATCCA.sub.10 G & GATCCT.sub.10 G cloned into the BamHI site (plasmid
 designated pT10). Target A.sub.5 GA.sub.4 : oligonucleotides TCGACT.sub.4
 CT.sub.5 G & TCGACA.sub.5 GA.sub.4 G cloned into the SalI site (plasmid
 pT9C). Target A.sub.2 GA.sub.2 GA.sub.4 : oligonucleotides GA.sub.2
 GA.sub.2 GA.sub.4 TGCA & GT.sub.4 CT.sub.2 CT.sub.2 CTGCA into the PstI
 site (plasmid pT8C2). The positions of the targets in the gel are
 indicated by bars to the left. A/G is an A+G sequence ladder of target
 P10.
 EXAMPLE 75
 Inhibition of Restriction Enzyme Cleavage by PNA (FIG. 14)
 A 2 .mu.g portion of plasmid pT10 was mixed with the indicated amount of
 PNA-T.sub.10 in 20 .mu.l TE buffer (10 mM Tris-HCl, 1 mM EDTA, pH 7.4) and
 incubated at 37.degree. C. for 120 min. 2 .mu.l 10.times.buffer (10 mM
 Tris-HCl, pH 7.5, 10 mM, MgCl.sub.2, 50 mM NaCl, 1 mM DTT). PvuII (2
 units) and BamHI (2 units) were added and the incubation was continued for
 60 min. The DNA was analyzed by gel electrophoresis in 5% polyacrylamide
 and the DNA was visualized by ethidium bromide staining.
 EXAMPLE 76
 Kinetics of PNA-T.sub.10 -dsDNA Strand Displacement Complex Formation (FIG.
 15)
 A mixture of 200 cps .sup.32 P-labeled EcoRI-PvuII fragment of pT10 (the
 large fragment labeled at the 3'-end of the EcoRI site), 0.5 .mu.g carrier
 calf thymus DNA, and 300 ng of PNA-T.sub.10 -LysNH.sub.2 in 100 .mu.l
 buffer (200 mM NaCl, 50 mM Na-acetate, pH 4.5, 1 mM ZnSO.sub.4) were
 incubated at 37.degree. C. At the times indicated, 50 U of S.sub.1
 nuclease was added to each of 7 samples and incubation was continued for 5
 min at 20.degree. C. The DNA was then precipitated by addition of 250
 .mu.l 2% K-acetate in ethanol and analyzed by electrophoresis in a 10%
 polyacrylamide sequencing gel. The amount of strand displacement complex
 was calculated from the intensity of the S.sub.1 -cleavage at the target
 sequence, as measured by densitometric scanning of autoradiographs.
 EXAMPLE 77
 Stability of PNA-dsDNA Complexes (FIG. 16)
 A mixture of 200 cps .sup.32 P-pT10 fragment, 0.5 .mu.g calf thymus DNA and
 300 ng of the desired PNA (either T.sub.10 -LysNH.sub.2, T.sub.8
 -LysNH.sub.2 or T.sub.6 -LysNH.sub.2) was incubated in 100 .mu.l 200 mM
 NaCl, 50 mM Na-acetate, pH 4.5, 1 mM ZnSO.sub.4 for 60 min at 37.degree.
 C. A 2 .mu.g portion of oligonucleotide GATCCA.sub.10 G was added and each
 sample was heated for 10 min at the temperature indicated, cooled in ice
 for 10 min and warmed to 20.degree. C. A 50 U portion of S.sub.1 nuclease
 was added and the samples treated and analyzed and the results quantified.
 EXAMPLE 78
 Inhibition of Transcription by PNA
 A mixture of 100 ng plasmid DNA (cleaved with restriction enzyme PvuII (see
 below) and 100 ng of PNA in 15 .mu.l 10 mM Tris-HCl, 1 mM EDTA, pH 7.4 was
 incubated at 37.degree. C. for 60 min. Subsequently, 4 .mu.l 5.times.
 concentrated buffer (0.2 M Tris-HCl (pH 8.0), 40 mM MgCl.sub.2, 10 mM
 spermidine, 125 mM NaCl) were mixed with 1 .mu.l NTP-mix (10 mM ATP, 10 mM
 CTP, 10 mM GTP, 1 MM UTP, 0.1 .mu.Ci/.mu.l .sup.32 P-UTP, 5 mM DTT, 2
 .mu.g/ml tRNA, 1 .mu.g/ml heparin) and 3 units RNA polymerase. Incubation
 was continued for 10 min at 37.degree. C. The RNA was then precipitated by
 addition of 60 .mu.l 2% postassium acetate in 96% ethanol at -20.degree.
 C. and analyzed by electrophoresis in 8% polyacrylamide sequencing gels.
 RNA transcripts were visualized by autoradiography. The following plasmids
 were used: pT8C2-KS/pA8G2-KS: oligonucleotides GA.sub.2 GA.sub.2 GA.sub.4
 GTGAC & GT.sub.4 CT.sub.2 CT.sub.2 CTGCA cloned into the PstI site of
 pBluescript-KS.sup.+ ; pT10-KS/pA10-KS (both orientations of the insert
 were obtained). pT10UV5: oligonucleotides GATCCA.sub.10 G & GATCCT.sub.10
 G cloned into the BamHI site of a pUC18 derivative in which the lac UV5 E.
 coli promoter had been cloned into the EcoRI site (Jeppesen, et al.,
 Nucleic Acids Res., 1988, 16, 9545).
 Using T.sub.3 -RNA polymerase, transcription elongation arrest was obtained
 with PNA-T.sub.8 C.sub.2 -LysNH.sub.2 and the pA8G2-KS plasmid having the
 PNA recognition sequence on the template strand, but not with pT8C2-KS
 having the PNA recognition sequence on the non-template strand. Similar
 results were obtained with PNA-T10-LysNH.sub.2 and the plasmids pA10-KS
 and pT10-KS. Using E. coli RNA polymerase and the pT10UV5 plasmid
 (A.sub.10 -sequence on the template strand) transcription elongation
 arrest was obtained with PNA-T.sub.10 -LysNH.sub.2.
 EXAMPLE 79
 Biological Stability of PNA
 A mixture of PNA-T.sub.5 (10 .mu.g) and a control, "normal" peptide (10
 .mu.g) in 40 .mu.l 50 mM Tris-HCl, pH 7.4 was treated with varying amounts
 of peptidase from porcine intestinal mucosa or protease from Streptomyces
 caespitosus for 10 min at 37.degree. C. The amount of PNA and peptide was
 determined by HPLC analysis (reversed phase C-18 column: 0-60%
 acetonitrile, 0.1% trifluoroacetic acid).
 At peptidase/protease concentrations where complete degradation of the
 peptide was observed (no HPLC peak) the PNA was still intact.
 EXAMPLE 80
 Inhibition of Gene Expression
 A preferred assay to test the ability of peptide nucleic acids to inhibit
 expression of the E2 mRNA of papillomavirus is based on the
 well-documented transactivation properties of E2. Spalholtz, et al., J.
 Virol., 1987, 61, 2128-2137. A reporter plasmid (E2RECAT) was constructed
 to contain the E2 responsive element, which functions as an E2 dependent
 enhancer. E2RECAT also contains the SV40 early promoter, an early
 polyadenylation signal, and the chloramphenicol acetyl transferase gene
 (CAT). Within the context of this plasmid, CAT expression is dependent
 upon expression of E2. The dependence of CAT expression on the presence of
 E2 has been tested by transfection of this plasmid into C127 cells
 transformed by BPV-1, uninfected C127 cells and C127 cells cotransfected
 with E2RECAT and an E2 expression vector.
 A. Inhibition of BPV-1 E2 Expression
 BPV-1 transformed C127 cells are plated in 12 well plates. Twenty four
 hours prior to transfection with E2RE1, cells are pretreated by addition
 of antisense PNAs to the growth medium at final concentrations of 5, 15
 and 30 mM. The next day cells are transfected with 10 .mu.g of E2RE1CAT by
 calcium phosphate precipitation. Ten micrograms of E2RE1CAT and 10 .mu.g
 of carrier DNA (PUC 19) are mixed with 62 .mu.l of 2 M CaCl.sub.2 in a
 final volume of 250 .mu.l of H.sub.2 O, followed by addition of 250 .mu.l
 of 2.times. HBSP (1.5 mM Na.sub.2 PO.sub.2. 10 mM KCl, 280 mM NaCl, 12 mM
 glucose and 50 mM HEPES, pH 7.0) and incubated at room temperature for 30
 minutes. One hundred microliters of this solution is added to each test
 well and allowed to incubate for 4 hours at 37.degree. C. After
 incubation, cells are glycerol shocked for 1 minute at room temperature
 with 15% glycerol in 0.75 mM Na.sub.2 PO.sub.2, 5 mM KCl, 140 mM NaCl, 6
 mM glucose and 25 mM HEPES, pH 7.0. After shocking, cells are washed 2
 times with serum free DMEM and refed with DMEM containing 10% fetal bovine
 serum and antisense oligonucleotide at the original concentration. Forty
 eight hours after transfection cells are harvested and assayed for CAT
 activity.
 For determination of CAT activity, cells are washed 2 times with phosphate
 buffered saline and collected by scraping. Cells are resuspended in 100
 .mu.l of 250 mM Tris-HCl, pH 8.0 and disrupted by freeze-thawing 3 times.
 Twenty four microliters of cell extract is used for each assay. For each
 assay the following are mixed together in an 1.5 ml Eppendorf tube and
 incubated at 37.degree. C. for one hour: 25 .mu.l of cell extract, 5 .mu.l
 of 4 mM acetyl coenzyme A, 18 .mu.l H.sub.2 O and 1 .mu.l .sup.14
 C-chloramphenicol, 40-60 mCi/mM. After incubation, chloramphenicol
 (acetylated and nonacetylated forms) is extracted with ethyl acetate and
 evaporated to dryness. Samples are resuspended in 25 .mu.l of ethyl
 acetate, spotted onto a TLC plate and chromatographed in
 chloroform:methanol (19:1). Chromatographs are analyzed by
 autoradiography. Spots corresponding to acetylated and nonacetylated
 .sup.14 C-chloramphenicol are excised from the TLC plate and counted by
 liquid scintillation for quantitation of CAT activity. Peptide nucleic
 acids that depress CAT activity in a dose dependent fashion are considered
 positives.
 B. Inhibition of HPV E2 Expression
 The assay for inhibition of human papillomavirus (HPV) E2 by peptide
 nucleic acids is essentially the same as that for BPV-1 E2. For HPV assays
 appropriate HPVs are cotransfected into either CV-1 or A431 cells with
 PSV2NEO using the calcium phosphate method described above. Cells which
 take up DNA are selected for by culturing in media containing the
 antibiotic G418. G418-resistant cells are then analyzed for HPV DNA and
 RNA. Cells expressing E2 are used as target cells for antisense studies.
 For each PNA, cells are pretreated as above, transfected with E2RE1CAT,
 and analyzed for CAT activity as above. Peptide nucleic acids are
 considered to have a positive effect if they can depress CAT activity in a
 dose dependent fashion.
 EXAMPLE 81
 Synthesis of PNA 15-mer Containing Four Naturally Occurring Nucleobases;
 H-[Taeg]-[Aaeg]-[Gaeg]-[Taeg]-[Taeg]-[Aaeg]-[Taeg]-[Caeg]-[Taeg]-[Caeg]-[T
 aeg]-[Aaeg]-[Taeg]-[Caeg]-[Taeg]-LYS-NH2
 The protected PNA was assembled onto a Boc-Lys(ClZ) modified MBHA resin
 with a substitution of approximately 0.145 mmol/g. Capping of uncoupled
 amino groups was only carried out before the incorporation of the
 BocGaeg-OH monomer.
 Synthesis was initiated on 100 mg (dry weight) of neutralised Boc-Lys
 (ClA)-MBHA resin that had been preswollen overnight in DCM. The
 incorporation of the monomers followed the protocol of Example 42, except
 at step 5 for the incorporation of the BocAaeg-OH monomer. Step 5 for the
 present synthesis involved addition of 4 equiv. diisopropyl carbodiimide
 (0.06 ml; 9.7 .mu.l) and 4 equiv. BocAaeg-OH (0.06 mmol; 32 mg) dissolved
 in 0.6 ml DCM/DMF (1:1, v/v) (final concentration of monomer 0.1M). The
 coupling reaction was allowed to proceed for 1.times.15 min and 1.times.60
 min. (recoupling).
 All qualitative Kaiser tests were negative (straw-yellow color with no
 coloration of the beads). The PNA-oligomer was cleaved and purified by the
 standard procedure. FAB-MS average mass found(calc.) (M+H) 4145.1
 (4146.1).
 EXAMPLE 82
 Hybridization of H-TAGTTATCTCTATCT-LysNH.sub.2

DNA -target pH Tm
 5'----3' 5 60.5
 5'----3' 7.2 43.0
 5'----3' 9 38.5
 5'----3' 5 64.5/49.0
 5'----3' 7.2 53.5
 5'----3' 9 51.5
 The fact that there is almost no loss in Tm in going from pH 7.2 to 9.0
 indicates that Hoogsteen basepairing is not involved. The increase in Tm
 in going from 7.2 to 5 is large for the parallel orientation and is
 probably due to the formation of a 2:1 complex. It is believed that the
 most favorable orientation in the Watson-Crick binding motif is the
 3'/N-orientation and that in the Hoogsteen motif the 5'/N-orientation is
 the most stable. Thus, it may be the case that the most stable complex is
 with the two PNA's strands anti parallel.
 There is apparently a very strong preference for a parallel orientation of
 the Hoogsteen strand. This seems to explain why even at pH 9 a 2:1 complex
 is seen with the 5'/N-orientation. Furthermore, it explains the small loss
 in going from pH 7.2 to 9 in the 3'/N, as this is probably a 1:1 complex.
 EXAMPLE 83
 Solid-Phase Synthesis of H-[Taeg].sub.2
 -Aaeg-Taeg-Caeg-Aaeg-Taeg-Caeg-Taeg-Caeg-Lys-NH2
 (a) Stepwise Assembly of
 Boc-[Taeg]2-A(Z)aeg-Taeg-C(Z)aeg-A(Z)aeg-Taeg-C(Z)aeg-Taeg-C(Z)aeg-Lys(ClZ
 )-MBHA Resin
 About 1 g of wet Boc-Lys(ClZ)-MBHA (0.28 mmol Lys/g) resin was placed in a
 5 ml SPPS reaction vessel.
 Boc-[Taeg]2-A(Z)aeg-Taeg-C(Z)aeg-A(Z)aeg-Taeg-C(Z)aeg-Taeg-C(Z)aeg-Lys(ClZ
 )-MBHA resin was assembled by in situ DCC coupling of the five first
 residues utilizing 0.16 M of BocC[Z]-OH, BocTaeg-OH or BocA(Z)aeg-OH,
 together with 0.16 M DCC in 2.0 ml 50% DMF/CH2Cl2 ("Synthetic Protocol 9")
 and by analogous in situ DIC coupling of the five last residues
 ("Synthetic Protocol 10"). Each coupling reaction was allowed to proceed
 for a total of 20-24 hrs with shaking. The synthesis was monitored by the
 ninhydrin reaction, which showed nearly quantitative incorporation of all
 residues except of the first A(Z)aeg residue, which had to be coupled
 twice. The total coupling yield was about 96% (first coupling, about 89%
 efficiency).
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]2-Aaeg-Taeg-Caeg-Aaeg-Taeg-Caeg-Taeg-Caeg-Lys-NH2
 The protected
 Boc-[Taeg]2-A(Z)aeg-Taeg-C(Z)aeg-A(Z)aeg-Taeg-C(Z)aeg-Taeg-C(Z)aeg-Lys(ClZ
 )-MBHA resin was treated as described in Example 27c to yield about 53.4 mg
 of crude material upon HF cleavage of 166.1 mg dry
 Boc-[Taeg]2-A(Z)aeg-Taeg-C(Z)aeg-A(Z)aeg-Taeg-C(Z)aeg-Taeg-C(Z)aeg-Lys(ClZ
 )-MBHA resin. The crude product (53.4 mg) was purified to give 18.3 mg of
 H-[Taeg]2-Aaeg-Taeg-Caeg-Aaeg-Taeg-Caeg-Taeg-Caeg-Lys-NH2. For (M+H)+, the
 calculated m/z value=2780.17 and the measured m/z value=2780.07.
 EXAMPLE 84
 Hybridization Properties of H-TTA TCA TCT C-Lys-NH.sub.2
 The title compound hybridized with the following oligonucleotides:

##STR10##
 A 375 mg portion of MBHA resin (loading 0.6 mmol/g) was allowed to swell
 over night in dichloromethane (DCM). After an hour in DMF/DCM, the resin
 was neutralized by washing 2 times with 5% diisopropylethylamine in DCM (2
 min.), followed by washing with DCM (2 ml; 6.times.1 min.)
 N,N'-di-Boc-aminoethyl glycine (41.9 mg; 0.132 mmol) disolved in 2 ml DMF
 was added to the resin, followed by DCC (64.9 mg; 0.315 mmol) dissolved in
 1 ml of DCM. After 2.5 hours, the resin was washed with DMF 3 times (1
 min.) and once with DCM (1 min.). The unreacted amino groups were then
 capped by treatment with acetic anhydride/DCM/pyridine (1 ml.backslash.2
 ml.backslash.2 ml) for 72 hours. After washing with DCM (2 ml; 4.times.1
 min), a Kaiser test showed no amino groups were present. The resin was
 deprotected and washed as described above. This was followed by reaction
 with 6-(Bocamino)-hexanoic acid DHBT ester (255.8 mg; 67 mmol) dissolved
 in DMF/DCM 1:1 (4 ml) overnight. After washing and neutraliation, a Kaiser
 test and an isatin test were performed. Both were negative. After capping,
 the elongenation of the PNA-chains was performed according to standard
 procedures for DCC couplings. All Kaiser tests performed after the
 coupling reactions were negative (Yellow). Qualitative Kaiser tests were
 done after deprotection of PNA units number 1, 2, 4, and 6. Each test was
 blue. The PNA oligomers were cleaved and purified by standard procedures.
 The amount of monomer and DCC used for each coupling was as follows (total
 volume 4.5 ml):

Oligodeoxynucleotide Tm (.degree. C.)
 5'-AAA AAA AAA A 43.5
 5-'AAA AGA AAA A 58.O
 5'-AAA AAG AAA A 60.0
 5'-AAA ACA AAA A 34.5
 5'-AAA AAC AAA A 34.5
 5'-AAA ATA AAA A 34.0
 5'-AAA AAT AAA A 36.0
 EXAMPLE 92
 Stepwise Assembly of
 H-[Taeg]-[Taeg]-[Taeg]-[Taeg]-[Aaeg]-[Taeg]-[Taeg]-[Taeg]-[Taeg]-[Taeg]-LY
 S-NH.sub.2
 Synthesis was initiated on a Boc-[Taeg].sub.5 -Lys(ClZ)-MBHA resin (from
 example 76) that had been preswollen overnight in DCM. The resin resembled
 approximately 100 mg (dry Weight) of Boc-Lys(ClZ)-MBHA resin (loading 0.15
 mmol/g). The incorporation of the monomers followed the protocol of
 example 55, except for step 5 (incorporation of the BocA(Z)aeg-OH
 monomer). New step 5 (incorporation of A(Z)aeg) involved addition of 4
 equiv. diisopropyl carbodiimide (0.06 mmol; 9.7 .mu.l) and 4 equiv.
 BocA(Z)aeg-OH (0.06 mmol; 32 mg) dissolved in 0.6 ml DCM/DMF (1:1, v/v)
 (final concentration of monomer 0.1 M). The coupling reaction was allowed
 to proceed for 1.times.15 min. and 1.times.60 min. (recoupling).
 Capping of uncoupled amino groups was only carried out before the
 incorporation of the BocA(Z)aeg-OH monomer. The coupling reaction was
 monitored by qualitative ninhydrin reaction (Kaiser test). All qualitative
 Kaiser tests were negative (straw-yellow color with no coloration of the
 beads). The PNA oligomer was cleaved and purified by standard procedures.
 EXAMPLE 94
 Hybridization properties of H-T.sub.4 AT.sub.5 -LysNH.sub.2

Oligodeoxynucleotide Tm
 5'-A4C2ACAC 38
 5' -CACAC2A4 55
 EXAMPLE 97
 Large Scale Solid-Phase Synthesis of H-[Taeg].sub.6 -Lys-NH.sub.2,
 H-[Taeg].sub.7 -Lys-NH.sub.2, H-[Taeg].sub.8 -Lys-NH.sub.2,
 H-[Taeg]-Lys-NH.sub.2, and H-[Taeg].sub.10 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA Resin and Shorter
 Fragments
 About 9 g of wet Boc-[Taeg].sub.3 -Lys(ClZ)-MBHA (see, Example 29b) resin
 was placed in a 60 ml SPPS reaction vessel. Boc-[Taeg].sub.5
 -Lys(ClZ)-MBHA resin was assembled by single coupling of both residues
 with 0.15 M of BocTaeg-OPfp in 10 ml neat CH.sub.2 Cl.sub.2 ("Synthetic
 Protocol 8"). Both coupling reactions were allowed to proceed overnight.
 The synthesis was monitored by the ninhydrin reaction, which showed close
 to quantitative incorporation of both residues. After deprotection of the
 N-terminal Boc group, about 4.5 g of H-[Taeg].sub.5 -Lys(ClZ)-MBHA was
 placed in a 20 ml SPPS reaction vessel and elongated to Boc-[Taeg].sub.8
 -Lys(ClZ)-MBHA by single in situ DCC coupling of all residues (close to
 quantitative, except for residue number eight) overnight with 0.2 M of
 BocTaeg-OH together with 0.2 M DCC in 7.5 ml neat CH.sub.2 Cl.sub.2
 ("Synthetic Protocol 9"). Before coupling of Taeg residues number seven
 and eight, respectively, small portions of H-[Taeg].sub.6 -Lys(ClZ)-MBHA
 and H-[Taeg].sub.7 -Lys(ClZ) -MBHA, respectively, were taken out for HF
 cleavage.
 Taeg residue number eight was coupled twice (overnight) to give close to
 quantitative incorporation. After deprotection of the N-terminal Boc
 group, a large portion of H-[Taeg].sub.8 -Lys(ClZ)-MBHA was taken out for
 HF cleavage. Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was assembled by
 double in situ DCC coupling of 0.16 M BocTaeg-OH, together with 0.16 M DCC
 in 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol" 9). Before
 coupling of the final residue, a small portion of H-[Taeg].sub.9
 -Lys(ClZ)-MBHA was taken out for HF cleavage.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.6
 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.6 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 14.0 mg of crude material upon HF
 cleavage of 52.4 mg dry H-Taeg].sub.6 -Lys(ClZ)-MBHA resin. The crude
 product was not purified (about 99% purity).
 (c) Cleavage, Purification, and Identification of H-[Taeg].sub.7
 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.7 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 5.2 mg of crude material upon HF
 cleavage of 58.4 mg dry H-Taeg].sub.7 -Lys(ClZ)-MBHA resin.
 (d) Cleavage, Purification, and Identification of H-[Taeg].sub.8
 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.8 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 114 mg of crude material upon HF
 cleavage of about 604 mg dry H-Taeg].sub.8 -Lys(ClZ)-MBHA resin.
 (e) Cleavage, Purification, and Identification of H-[Taeg].sub.9
 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.9 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 19.3 mg of crude material upon HF
 cleavage of 81.0 mg dry H-Taeg].sub.9 -Lys(ClZ)-MBHA resin.
 (f) Cleavage, Purification, and Identification of H-[Taeg].sub.10
 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 141 mg of crude material upon HF
 cleavage of about 417 mg dry H-Taeg].sub.10 -Lys(ClZ)-MBHA resin.
 (g) Synthetic Protocol 8 (General Protocol)
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 3.times.1 min
 and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 6.times.1 min; (3)
 neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19, v/v) , 3.times.2 min;
 (4) washing with CH.sub.2 Cl.sub.2, 6.times.1 min, and drain for 1 min;
 (5) at some stages of the synthesis, 2-5 mg sample of PNA-resin is taken
 out and dried thoroughly for a ninhydrin analysis to determine the
 substitution; (6) addition of Boc-protected PNA monomer (Pfp ester); the
 coupling reaction was allowed to proceed for a total of X hrs shaking; (7)
 washing with DMF, 1.times.2 min; (8) washing with CH.sub.2 Cl.sub.2,
 4.times.1 min; (9) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2.times.2 min; (10) washing with CH.sub.2 Cl.sub.2, 6.times.1 min;
 (11) occasionally, 2-5 mg sample of protected PNA-resin is taken out and
 dried thoroughly for a ninhydrin analysis to determine the extent of
 coupling; (12) at some stages of the synthesis, unreacted amino groups are
 blocked by acetylation with a mixture of acetic
 anhydride/pyridine/CH.sub.2 Cl.sub.2 (1:1:2, v/v/v) for 2 h followed by
 washing with CH.sub.2 Cl.sub.2, 6.times.1 min, and, occasionally,
 ninhydrin analysis.
 EXAMPLE 98
 Solid-Phase Synthesis of H-[Taeg]4-Caeg-[Taeg]5-Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg]4-C[Z]aeg-[Taeg]5-Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg]5-Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS
 reaction vessel. Boc-[Taeg]4-C[Z]aeg-[Taeg]5-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC coupling of all residues utilizing 0.16 M of
 BocC[Z]aeg-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2
 or 0.16 M BocTaeg-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was allowed to
 proceed for a total of 20-24 hrs with shaking. The synthesis was monitored
 by the ninhydrin reaction, which showed about 98% incorporation of C[Z]aeg
 and close to quantitative incorporation of all the Taeg residues.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]4-C[Z]aeg-[Taeg]5-Lys-NH.sub.2
 The protected Boc-[Taeg]4-C[Z]aeg-[Taeg]5-Lys(ClZ)-MBHA resin was treated
 as described in Example 27c to yield about 22.5 mg of crude material upon
 HF cleavage of 128.2 mg dry H-[Taeg]4-C[Z]aeg-[Taeg]5-Lys(ClZ)-MBHA resin.
 Crude product (5.8 mg) was purified to give 3.1 mg of
 H-[Taeg]4-Caeg-[Taeg]5-Lys-NH.sub.2.
 (c) Synthetic Protocol 9 (General Protocol)
 (1) Boc-deprotection with TFA/CH.sub.2 Cl.sub.2 (1:1, v/v), 3.times.1 min
 and 1.times.30 min; (2) washing with CH.sub.2 Cl.sub.2, 6.times.1 min; (3)
 neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19, v/v), 3.times.2 min;
 (4) washing with CH.sub.2 Cl.sub.2, 6.times.1 min, and drain for 1 min;
 (5) at some stages of the synthesis, 2-5 mg sample of PNA-resin is taken
 out and dried thoroughly for a ninhydrin analysis to determine the
 substitution; (6) addition of Boc-protected PNA monomer (free acid) in X
 ml DMF followed by addition of DCC in X ml CH.sub.2 Cl.sub.2 ; the
 coupling reaction was allowed to proceed for a total of Y hrs shaking; (7)
 washing with DMF, 1.times.2 min; (8) washing with CH.sub.2 Cl.sub.2,
 4.times.1 min; (9) neutralization with DIEA/CH.sub.2 Cl.sub.2 (1: 19,
 v/v), 2.times.2 min; (10) washing with CH.sub.2 Cl.sub.2, 6.times.1 min;
 (11) occasionally, 2-5 mg sample of protected PNA-resin is taken out and
 dried thoroughly for a ninhydrin analysis to determine the extent of
 coupling; (12) at some stages of the synthesis, unreacted amino groups are
 blocked by acetylation with a mixture of acetic
 anhydride/pyridine/CH.sub.2 Cl.sub.2 (1:1:2, v/v/v) for 2 h followed by
 washing with CH.sub.2 Cl.sub.2, 6.times.1 min, and, occasionally,
 ninhydrin analysis.
 EXAMPLE 99
 Solid-Phase Synthesis of H-[Taeg]4-(NBaeg)-[Taeg]5-Lys-NH.sub.2
 (NB.dbd.COCH3)
 (a) Stepwise Assembly of Boc-[Taeg]4-(NBaeg)-[Taeg]5-Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg]5-Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS
 reaction vessel. Boc-[Taeg]4-(NBaeg)-[Taeg]5-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC coupling utilizing 0.16 M of Boc(NBaeg)-OH
 together with 0.16 M DCC in 2.0 ml neat CH.sub.2 Cl.sub.2 or 0.16 M
 BocTaeg-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2
 ("Synthetic Protocol 9"). Each coupling reaction was allowed to proceed
 for a total of 20-24 hrs with shaking. The NBaeg residue was coupled three
 times and the Taeg residues were all coupled once. The synthesis was
 monitored by the ninhydrin reaction which showed &gt;99% total incorporation
 of NBaeg (about 88% after the first coupling and about 93% after the
 second coupling) and close to quantitative incorporation of all the Taeg
 residues.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]4-(NBaeg)-[Taeg]5-Lys-NH.sub.2
 The protected Boc-[Taeg]4-(NBaeg)-[Taeg]5-Lys(ClZ)-MBHA resin was treated
 as described in Example 27c to yield about 33.6 mg of crude material upon
 HF cleavage of 108.9 mg dry H-[Taeg]4-(NBaeg)-[Taeg]5-Lys(ClZ)-MBHA resin.
 Crude product (20.6 mg) was purified to give 4.6 mg of
 H-[Taeg]4-(NBaeg)-[Taeg]5-Lys-NH.sub.2. For (M+H)+, the calculated m/z
 value was 2683.12 and the measured m/z value was 2683.09.
 EXAMPLE 100
 Solid-Phase Synthesis of H-[Taeg]4-aeg-[Taeg]5-Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg]4-aeg-[Taeg]5-Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg]5-Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS
 reaction vessel. Boc-[Taeg]4-aeg-[Taeg]5-Lys(ClZ)-MBHA resin was assembled
 by in situ DCC single coupling of all residues utilizing: (1) 0.16 M of
 Bocaeg-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2 or
 (2) 0.16 M BocTaeg-OH together with (2) 0.16 M DCC in 2.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking. The synthesis
 was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]4-aeg-[Taeg]5-Lys-NH.sub.2
 The protected Boc-[Taeg]4-aeg-[Taeg]5-Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 22.2 mg of crude material upon HF
 cleavage of 126.0 mg dry H-[Taeg]4-aeg-[Taeg]5-Lys(ClZ)-MBHA resin. Crude
 product (22.2 mg) was purified to give 7.6 mg of
 H-[Taeg]4-aeg-[Taeg]5-Lys-NH.sub.2. For (M+H)+, the calculated m/z value
 was 2641.11 and the measured m/z value was 2641.16.
 EXAMPLE 101
 Solid-Phase Synthesis of H-[Taeg]4-Gly-[Taeg]5-Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg]4-Gly-[Taeg]5-Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg]5-Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS
 reaction vessel. Boc-[Taeg]4-Gly-[Taeg]5-Lys(ClZ)-MBHA resin was assembled
 by in situ DCC single coupling of all residues utilizing: (1) 0.16 M of
 BocGly-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2 or
 (2) 0.16 M BocTaeg-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was allowed to
 proceed for a total of 20-24 hrs with shaking. The synthesis was monitored
 by the ninhydrin reaction, which showed close to quantitative
 incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]4-Gly-[Taeg]5-Lys-NH.sub.2
 The protected Boc-[Taeg]4-Gly-[Taeg]5-Lys(ClZ)-MBHA resin was treated as
 described in Example 28c to yield about 45.0 mg of crude material upon HF
 cleavage of 124.1 mg dry H-[Taeg]4-Gly-[Taeg]5-Lys(ClZ)-MBHA resin. Crude
 product (40.4 mg) was purified to give 8.2 mg of
 H-[Taeg]4-Gly-[Taeg]5-Lys-NH.sub.2.
 EXAMPLE 102
 Solid-Phase Synthesis of H-[Taeg]4-Gly2-[Taeg]5-Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg]4-Gly2-[Taeg]5-Lys(ClZ)-MBHA Resin
 About 1 g of wet Boc-[Taeg]5-Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS
 reaction vessel.
 Boc-[Taeg]4-[C[Z]aeg]2-Taeg-C[Z]aeg-Taeg-C[Z]aeg-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC single coupling of all residues utilizing: (1)
 0.16 M of BocGly-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 or (2) 0.16 M BocTaeg-OH together with 0.16, M DCC in 2.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking. The synthesis
 was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]4-Gly2-[Taeg]5-Lys-NH.sub.2
 The protected Boc-[Taeg]4-Gly2-[Taeg]5-Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 32.6 mg of crude material upon HF
 cleavage of 156.6 mg dry H-[Taeg]4-Gly2-[Taeg]5-Lys(ClZ)-MBHA resin. Crude
 product (30 mg) was purified to give 7.8 mg of
 H-[Taeg]4-Gly2-[Taeg]5-Lys-NH.sub.2. For (M+H)+, the calculated m/z value
 was 2655.09 and the measured m/z value was 2655.37.
 EXAMPLE 103
 Solid-Phase Synthesis of H-[Taeg]4-[Caeg]2-Taeg-Caeg-Taeg-Caeg-Lys-NH.sub.2
 (a) Stepwise Assembly of
 Boc-[Taeg]4-[C[Z]aeg]2-Taeg-C[Z]aeg-Taeg-C[Z]aeg-Lys(Clz)-MBHA Resin
 About 1.5 g of wet Boc-Lys(ClZ)-MBHA (0.28 mmol Lys/g) resin was placed in
 a 5 ml SPPS reaction vessel.
 Boc-[Taeg]4-[C[Z]aeg]2-Taeg-C[Z]aeg-Taeg-C[Z]aeg-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC single coupling of all residues utilizing: (1)
 0.16 M of BocC[Z]-OH together with 0.16 M DCC in 2.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 or (2) 0.16 M BocTaeg-OH together with 0.16 M DCC in 2.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking. The synthesis
 was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.4
 -[Caeg].sub.2 -Taeg-Caeg-Taeg-Caeg-Lys-NH.sub.2
 The protected
 Boc-[Taeg]4-[C[Z]aeg]2-Taeg-C[Z]aeg-Taeg-C[Z]aeg-Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 52.1 mg of crude
 material upon HF cleavage of 216.7 mg dry
 H-[Taeg]4-[C[Z]aeg]2-Taeg-C[Z]aeg-Taeg-C[Z]aeg-Lys(CLZ)-MBHA resin. Crude
 product (30.6 mg) was purified to give 6.2 mg of
 H-[Taeg]4-[Caeg]2-Taeg-Caeg-Taeg-Caeg-Lys-NH.sub.2. For (M+H)+ the
 calculated m/z value was 2747.15 and the measured m/z value was 2746.78.
 EXAMPLE 104
 Solid-Phase Synthesis of
 H-Caeg-Taeg-Caeg-Taeg-[Caeg]3-Taeg-Caeg-Taeg-Lys-NH.sub.2
 (a) Stepwise Assembly of
 Boc-C[Z]aeg-Taeg-C[Z]aeg-Taeg-[C[Z]aeg]3-Taeg-C[Z]aeg-Taeg-Lys(ClZ)-MBHA
 Resin
 About 1.5 g of wet Boc-Lys(ClZ)-MBHA (0.28 mmol Lys/g) resin was placed in
 a 5 ml SPPS reaction vessel.
 Boc-C[Z]aeg-Taeg-C[Z]aeg-Taeg-[C[Z]aeg]3-Taeg-C[Z]aeg-Taeg-Lys(ClZ)-MBHA
 resin was assembled by in situ DCC single coupling of all residues
 utilizing: (1) 0.16 M of BocC[Z]-OH together with 0.16 M DCC in 2.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 or (2) 0.16 M BocTaeg-OH together with 0.16 M DCC in
 2.0 ml 50% DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling
 reaction was allowed to proceed for a total of 20-24 hrs with shaking. The
 synthesis was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of
 H-Caeg-Taeg-Caeg-Taeg-[Caeg]3-Taeg-Caeg-Taeg-Lys-NH 2
 The protected
 Boc-C[Z]aeg-Taeg-C[Z]aeg-Taeg-[C[Z]aeg]3-Taeg-C[Z]aeg-TaegLys(ClZ)-MBHA
 resin was treated as described in Example 27c to yield about 56.1 mg of
 crude material upon HF cleavage of 255.0 mg dry
 H--C[Z]aeg-Taeg-C[Z]aeg-Taeg-[C[Z]aeg]3-Taeg-C[Z]aeg -TaegLys(ClZ)-MBHA
 resin. Crude product (85.8 mg) was purified to give 46.2 mg of
 H-Caeg-Taeg-Caeg-Taeg-[Caeg]3-Taeg-Caeg-Taeg-LysNH.sub.2. For (M+H)+ the
 calculated m/z value was 2717.15 and the measured m/z value was 2716.93.
 EXAMPLE 105
 Solid-Phase Synthesis of H-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2,
 H-Caeg-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2, and
 H-Tyr-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2
 (a) Stepwise Assembly of
 Boc-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA Resin,
 Boc-Caeg-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA Resin, and
 Boc-Tyr(BrZ)-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA Resin
 About 3 g of wet Boc-Lys(ClZ)-MBHA (0.28 mmol Lys/g) resin was placed in a
 20 ml SPPS reaction vessel.
 Boc-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC single coupling of all residues utilizing: (1)
 0.16 M of BocC[Z]-OH together with 0.16 M DCC in 3.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 or (2) 0.16 M BocTaeg-OH together with 0.16 M DCC in 3.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking. The synthesis
 was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues. After deprotection of the
 N-terminal Boc group, half of the PNA-resin was coupled quantitatively
 onto Tyr(BrZ)-OH and a small portion was coupled quantitatively onto one
 more Caeg residue. Both couplings employed the above-mentioned synthetic
 protocol.
 (b) Cleavage, Purification, and Identification of
 H-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2
 The protected Boc-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin
 was treated as described in Example 27c to yield about 50.9 mg of crude
 material upon HF cleavage of 182.5 mg dry
 H-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin. Crude product
 (50.9) mg was purified to give 13.7 mg of
 H-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-LysNH.sub.2. For (M+H)+ the calculated
 m/z value was 2466.04; the m/z value was not measured.
 (c) Cleavage, Purification, and Identification of
 H-Tyr-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2
 The protected
 Boc-Tyr(BrZ)-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 60.8 mg of crude
 material upon HF cleavage of 188.8 mg dry
 H-Tyr(BrZ)-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin.
 Crude product (60.8 mg) was purified to give 20.7 mg of
 H-Tyr-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-LysNH.sub.2. For (M+H)+ the
 calculated m/z value was 2629.11 and the measured m/z value was 2629.11.
 (d) Cleavage, Purification, and Identification of
 H-Caeg-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-Lys-NH.sub.2
 The protected
 Boc-C(Z)aeg-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 11.7 mg of crude
 material upon HF cleavage of 42.0 mg dry
 H--C(Z)aeg-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin.
 Crude product (11.6 mg) was purified to give 3.1 mg of
 H-Caeg-[Taeg]2-[Caeg]3-[Taeg]2-[Caeg]2-LysNH.sub.2. For (M+H)+ the
 calculated m/z value was 2717.15; the m/z value was not measured.
 EXAMPLE 106
 Solid-Phase Synthesis of H-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2,
 H-Taeg-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2, and
 H-Tyr-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2
 (a) Stepwise Assembly of
 Boc-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA Resin,
 Boc-Taeg-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA Resin, and
 Boc-Tyr(BrZ)-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA Resin
 About 3 g of wet Boc-Lys(ClZ)-MBHA (0.28 mmol Lys/g) resin was placed in a
 20 ml SPPS reaction vessel.
 Boc-[Taeg]2-[C(Z)aeg]3-[Taeg]2-[C(Z)aeg]2-Lys(ClZ)-MBHA resin was
 assembled by in situ DCC single coupling of all residues utilizing: (1)
 0.16 M of BocC[Z]-OH together with 0.16 M DCC in 3.0 ml 50% DMF/CH.sub.2
 Cl.sub.2 or (2) 0.16 M BocTaeg-OH together with 0.16 M DCC in 3.0 ml 50%
 DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9"). Each coupling reaction was
 allowed to proceed for a total of 20-24 hrs with shaking. The synthesis
 was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues. After deprotection of the
 N-terminal Boc group, half of the PNA-resin was coupled quantitatively
 onto Tyr(BrZ)-OH and a small portion was coupled quantitatively onto one
 more Taeg residue. Both couplings employed the above-mentioned synthetic
 protocol.
 (b) Cleavage, Purification, and Identification of
 H-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys-NH.sub.2
 The protected Boc-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA resin
 was treated as described in Example 27c to yield about 57.6 mg of crude
 material upon HF cleavage of 172.7 mg dry
 H-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA resin. Crude product
 (57.6 mg) was purified to give 26.3 mg of
 H-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2. For (M+H)+ the calculated
 m/z value was 2466.04; the m/z value was not measured.
 (c) Cleavage, Purification, and Identification of
 H-Tyr-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys-NH.sub.2
 The protected
 Boc-Tyr(BrZ)-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 57.6 mg of crude
 material upon HF cleavage of 172.7 mg dry
 H-Tyr(BrZ)-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA resin.
 Crude product (47.1 mg) was purified to give 13.4 mg of
 H-Tyr-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2. For (M+H)+ the
 calculated m/z value was 2629.11 and the measured m/z value was 2629.11.
 (d) Cleavage, Purification, and Identification of
 H-Taeg-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys-NH.sub.2
 The protected Boc-Taeg-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA
 resin was treated as described in Example 27c to yield about 53.4 mg of
 crude material upon HF cleavage of 42.4 mg dry
 H-Taeg-[C(Z)aeg]2-[Taeg]2-[C(Z)aeg]3-[Taeg]2-Lys(ClZ)-MBHA resin. Crude
 product (11.9 mg) was purified to give 4.3 mg of
 H-Taeg-[Caeg]2-[Taeg]2-[Caeg]3-[Taeg]2-Lys-NH.sub.2. For (M+H)+ the
 calculated m/z value was 2732.15; the m/z value was not measured.
 (c) Synthetic Protocol 10 (General Protocol)
 Same protocol as "Synthetic Protocol 9", except that DCC has been replaced
 with DIC.
 EXAMPLE 107
 Synthesis of the Backbone Moiety for Scale up by Reductive Amination
 (a) Preparation of (bocamino)acetaldehyde
 3-Amino-1,2-propanediol(80.0 g; 0.88 mol) was dissolved in water (1500 ml)
 and the solution was cooled to 4.degree. C., whereafter Boc anhydride (230
 g; 1.05 mol) was added at once. The solution was gently heated to room
 temperature with a water bath. The pH was kept at 10.5 by the dropwise
 addition of sodium hydroxide. Over the course of the reaction a total of
 70.2 g NaOH, dissolved in 480 ml water, was added. After stirring
 overnight, ethyl acetate (1000 ml) was added and the mixture was cooled to
 0.degree. C. and the pH was adjusted to 2.5 by the addition of 4 M
 hydrochloric acid. The ethyl acetate layer was removed and the acidic
 aqueous solution was extracted with more ethyl acetate (8.times.500 ml).
 The combined ethyl acetate solution was reduced to a volume of 1500 ml
 using a rotary evaporator. The resulting solution was washed with half
 saturated potassium hydrogen sulphate (1500 ml) and then with saturated
 sodium chloride. It then was dried over magnesium sulphate and evaporated
 to dryness, in vacuo. Yield. 145.3 g (86%)
 3-Bocamino-1,2-propanediol (144.7 g; 0.757 mol) was suspended in water (750
 ml) and potassium periodate (191.5 g; 0.833 mol) was added. The mixture
 was stirred under nitrogen for 2.5 h and the precipitated potassium iodate
 was removed by filtration and washed once with water (100 ml). The aqueous
 phase was extracted with chloroform (6.times.400 ml). The chloroform
 extracts were dried and evaporated to dryness, in vacuo. Yield 102 g (93%)
 of an oil. The (bocamino)acetaldehyde was purified by kugelrohr
 distillation at 84.degree. C. and 0.3 mmHg in two portions. The yield 79 g
 (77%) of a colorless oil.
 (b) Preparation of (N'-bocaminoethyl)glycine Methyl Ester
 Palladium on carbon (10%; 2.00 g) was added to a solution of
 (bocamino)acetaldehyde (10.0 g; 68.9 mmol) in methanol (150 ml) at
 0.degree. C. Sodium acetate (11.3 g; 138 mmol) in methanol (150 ml), and
 glycine methyl ester hydrochloride (8.65 g; 68.9 mmol) in methanol (75 ml)
 then were added. The mixture was hydrogenated at atmospheric pressure for
 2.5 h, then filtered through celite and evaporated to dryness, in vacuo.
 The material was redissolved in water (150 ml) and the pH was adjusted to
 8.0 with 0.5 N NaOH. The aqueous solution was extracted with methylene
 chloride (5.times.150 ml). The combined extracts were dried over sodium
 sulphate and evaporated to dryness, in vacuo. This resulted in 14.1 g
 (88%) of (N'-bocaminoethyl)glycine methyl ester. The crude material was
 purified by kugelrohr destination at 120.degree. C. and 0.5 mmHg to give
 11.3 g (70%) of a colorless oil. The product had a purity that was higher
 than the material produced in example 26 according to tlc-analysis (10%
 methanol in methylene chloride).
 Alternatively, sodium cyanoborohydride can be used as reducing agent
 instead of hydrogen (with Pd(C) as catalyst), although the yield (42%) was
 lower.
 (c) Preparation of (N'-bocaminoethyl)glycine Ethyl Ester
 The title compound was prepared by the above procedure with glycine ethyl
 ester hydrochloride substituted for glycine methyl ester hydrochloride.
 Also, the solvent used was ethanol. The yield was 78%.
 EXAMPLE 108
 Solid-Phase Synthesis of H-Tyr-[Taeg].sub.10 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-Tyr(BrZ)-[Taeg].sub.10 -Lys(ClZ)-MBHA Resin
 About 0.2 g of wet Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was placed in a 5
 ml SPPS reaction vessel. Boc-Tyr(BrZ)-[Taeg].sub.10 -Lys(ClZ)-MBHA resin
 was assembled by standard in situ DCC coupling utilizing 0.32 M of
 BocCTyr(BrZ)-OH together with 0.32 M DCC in 3.0 ml neat CH.sub.2 Cl.sub.2
 overnight. The ninhydrin reaction showed about 97% incorporation of
 BocTyr(BrZ).
 (b) Cleavage, Purification, and Identification of H-Tyr-[Taeg].sub.10
 -Lys-NH.sub.2
 The protected Boc-Tyr(BrZ)-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was treated
 as described in Example 27c to yield about 5.5 mg of crude material upon
 HF cleavage of 20.7 mg dry H-Tyr(BrZ)-[Taeg].sub.10 -Lys(ClZ)-MBHA resin.
 The crude product was purified to give 2.5 mg of H-Tyr-[Taeg].sub.10
 -Lys-NH.sub.2.
 EXAMPLE 109
 Solid-Phase Synthesis of Dansyl-[Taeg].sub.10 -Lys-NH.sub.2
 (a) Stepwise Assembly of Dansyl-[Taeg].sub.10 -Lys(ClZ)-MBHA Resin
 About 0.3 g of wet Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was placed in a 5
 ml SPPS reaction vessel. Dansyl-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was
 assembled by coupling of 0.5 M dansyl-Cl in 2.0 ml neat pyridine
 overnight. The ninhydrin reaction showed about 95% incorporation of
 dansyl.
 (b) Cleavage, Purification, and Identification of Dansyl-[Taeg].sub.10
 -Lys-NH.sub.2
 The protected dansyl-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 12 mg of crude material upon HF
 cleavage of 71.3 mg dry dansyl-[Taeg].sub.10 -Lys(ClZ)-MBHA resin. The
 crude product was purified to give 5.4 mg of dansyl-[Taeg].sub.10
 -Lys-NH.sub.2.
 EXAMPLE 110
 Solid-Phase Synthesis of Gly-Gly-His-[Taeg].sub.10 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-Gly-Gly-His(Tos)-[Taeg].sub.10 -Lys(ClZ)-MBHA
 Resin
 About 0.05 g of Boc-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was placed in a 5 ml
 SPPS reaction vessel. Boc-Gly-Gly-His(Tos)-[Taeg].sub.10 -Lys(ClZ)-MBHA
 resin was assembled by standard double in situ DCC coupling of
 Boc-protected amino acid (0.1 M) in 2.5 ml 25% DMF/CH.sub.2 Cl.sub.2,
 except for the first coupling of BocHis (Tos), which was done by using a
 preformed symmetrical anhydride (0.1M) in 25% DMF/CH.sub.2 Cl.sub.2. All
 couplings were performed overnight and ninhydrin reactions were not
 carried out.
 (b) Cleavage, Purification, and Identification of Gly-Gly-His-[Taeg].sub.10
 -Lys-NH.sub.2
 The protected Boc-Gly-Gly-His(Tos)-[Taeg].sub.10 -Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 10.3 mg of crude
 material (about 40% purity) upon HF cleavage of 34.5 mg dry
 Boc-Gly-Gly-His(Tos)-[Taeg].sub.10 -Lys(ClZ)-MBHA resin. A small portion
 of the crude product (taken out before lyophilization) was purified to
 give 0.1 mg of Gly-Gly-His-[Taeg].sub.10 -Lys-NH.sub.2.
 EXAMPLE 111
 Solid-Phase Synthesis of H-[Taeg].sub.5 -[Caeg].sub.2 -NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.5 -[C(Z)aeg].sub.2 -MBHA Resin
 About 0.2 g of MBHA resin was placed in a 3 ml SPPS reaction vessel and
 neutralized. The loading was determined to be about 0.64 mmol/g.
 BocC(Z)aeg-OPfp was coupled onto the resin using a concentration of 0.13 M
 in 2.5 ml 25% phenol//CH.sub.2 Cl.sub.2. The ninhydrin analysis showed a
 coupling yield of about 40%. The remaining free amino groups were
 acetylated as usual. Boc-[Taeg].sub.5 -[C(Z)aeg].sub.2 -MBHA resin was
 assembled by single in situ DCC coupling of the next residue utilizing
 0.11 M of BocC(Z)aeg-OH together with 0.11 M DCC in 2.5 ml 50%
 DMF/CH.sub.2 Cl.sub.2 and by coupling with 0.13 M BocTaeg-OPfp in neat
 CH.sub.2 Cl.sub.2 for the remaining residues ("Synthetic Protocol 8").
 Each coupling reaction was allowed to proceed with shaking overnight. The
 synthesis was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.5
 -[Caeg].sub.2 -NH.sub.2
 The protected Boc-[Taeg].sub.5 -[C(Z)aeg].sub.2 -MBHA resin was treated as
 described in Example 27c to yield about 21.7 mg of crude material (&gt;80%
 purity) upon HF cleavage of 94.8 mg dry H-[Taeg].sub.5 -[C(Z)aeg].sub.2
 -MBHA resin. Crude product (7.4 mg) was purified to give 2.0 mg of
 H-[Taeg].sub.5 -[Caeg].sub.2 -NH.sub.2 (&gt;99% purity).
 EXAMPLE 112
 Solid-Phase Synthesis of H-[Taeg].sub.3 -Caeg-[Taeg].sub.4 -NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.3 -C (Z) aeg-[Taeg].sub.4 -MBHA
 Resin
 About 0.2 g of the above-mentioned MBHA resin was placed in a 5 ml SPPS
 reaction vessel and neutralized. Boc-[Taeg].sub.3 -C(Z)aeg-[Taeg].sub.4
 -MBHA resin was assembled by single in situ DCC coupling of the C(Z)aeg
 residue utilizing 0.13 M of BocC[Z]aeg-OH together with 0.13 M DCC in 2.5
 ml 50% DMF/CH.sub.2 Cl.sub.2 and by coupling the Taeg residues with 0.13 M
 BocTaeg-OPfp in 2.5 ml neat CH.sub.2 Cl.sub.2. Each coupling reaction was
 allowed to proceed with shaking overnight. The synthesis was monitored by
 the ninhydrin reaction, which showed close to quantitative incorporation
 of all the residues.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.3
 -Caeg-[Taeg].sub.4 -NH.sub.2
 The protected Boc-[Taeg].sub.3 -C(Z)aeg-[Taeg].sub.4 -MBHA resin was
 treated as described in Example 27c to yield about 44.4 mg of crude
 material upon HF cleavage of about 123 mg dry H-[Taeg].sub.3
 -C(z)aeg-[Taeg].sub.4 -MBHA resin. Crude product (11.0 mg) was purified to
 give 3.6 mg of H-[Taeg].sub.3 -Caeg-[Taeg].sub.4 -NH.sub.2.
 EXAMPLE 113
 Solid-Phase Synthesis of H-Taeg-Caeg-[Taeg].sub.8 -LysNH.sub.2
 (a) Stepwise Assembly of Boc-Taeg-C(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-MBHA Resin
 About 0.3 g of wet Boc-[Taeg].sub.8 -Lys(ClZ)-MBHA resin was placed in a 3
 ml SPPS reaction vessel. Boc-Taeg-C(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-MBHA
 resin was assembled by single in situ DCC coupling overnight of the
 C(Z)aeg residue ("Synthetic Protocol" 9) utilizing 0.2 M of BocC[Z]aeg-OH
 together with 0.2 M DCC in 2.5 ml 50% DMF/CH.sub.2 Cl.sub.2 (incorporation
 was about 80% as judged by ninhydrin analysis; remaining free amino groups
 were acetylated) and by overnight coupling the Taeg residue with 0.15 M
 BocTaeg-OPfp in 2.5 ml neat CH.sub.2 Cl.sub.2 (nearly quantitatively).
 (b) Cleavage, Purification, and Identification of H-Taeg-Caeg-[Taeg].sub.8
 -LysNH.sub.2
 The protected Boc-Taeg-C(Z)aeg-[Taeg].sub.8 -Lys(ClZ)-MBHA resin was
 treated as described in Example 27c to yield about 22.3 mg of crude
 material upon HF cleavage of about 76.5 mg dry H-Taeg-C(Z)aeg-[Taeg].sub.8
 -Lys(ClZ)-MBHA resin. Crude product (6.7 mg) was purified to give 2.6 mg
 of H-Taeg-Caeg-[Taeg].sub.8 -LysNH.sub.2. For (M+H).sup.+ the calculated
 m/z value was 2792.15 and the measured m/z value was 2792.21.
 EXAMPLE 114
 Solid-Phase Synthesis of H-Caeg-[Taeg].sub.5 -Lys-NH.sub.2 and
 H-[Taeg].sub.2 -Caeg-[Taeg].sub.5 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.5
 -Lys(ClZ)-MBHA Resin
 About 0.5 g of wet Boc-[Taeg].sub.5 -Lys(ClZ)-MBHA resin was placed in a 5
 ml SPPS reaction vessel. Boc-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.5
 -Lys(ClZ)-MBHA resin was assembled by single in situ DCC coupling of all
 residues utilizing: (1) 0.12 M of BocC[Z]aeg-OH together with 0.12 M DCC
 in 3.0 ml 50% DMF/CH.sub.2 Cl.sub.2 or (2) 0.12 M BocTaeg-OH together with
 0.12 M DCC in 3.0 ml 50% DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9").
 Each coupling reaction was allowed to proceed overnight with shaking. The
 synthesis was monitored by the ninhydrin reaction, which showed close to
 quantitative incorporation of all the residues. During the synthesis, a
 small portion of H--C(Z)aeg-[Taeg].sub.5 -Lys(ClZ)-MBHA resin was taken
 out for HF cleavage.
 (b) Cleavage, Purification, and Identification of H-Caeg-[Taeg].sub.5
 -Lys-NH.sub.2
 The protected Boc-C[Z]aeg-[Taeg].sub.5 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 3.0 mg of crude material upon HF
 cleavage of 37.5 mg dry H--C[Z]aeg-[Taeg].sub.5 -Lys(ClZ)-MBHA resin.
 About 0.7 mg of the crude product was purified to give about 0.5 mg of
 H-Caeg-[Taeg].sub.5 -Lys-NH.sub.2.
 (c) Cleavage, Purification, and Identification of H-[Taeg].sub.2
 -Caeg-[Taeg].sub.5 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.2 -C[Z]aeg-[Taeg].sub.5 -Lys(ClZ)-MBHA resin
 was treated as described in Example 27c to yield about 37.7 mg of crude
 material upon HF cleavage of 118.6 mg dry H-[Taeg].sub.2
 -C[Z]aeg-[Taeg].sub.5 -Lys(ClZ)-MBHA resin.
 EXAMPLE 115
 Solid-Phase Synthesis of H-[Caeg].sub.5 -Lys-NH.sub.2, H-[Caeg].sub.6
 -Lys-NH.sub.2, H-[Caeg].sub.8 -Lys-NH.sub.2, and H-[Caeg].sub.10
 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[C(Z)aeg].sub.10 -Lys(ClZ)-MBHA Resin and
 Shorter Fragments.
 About 5 g of wet Boc-Lys(ClZ)-MBHA resin (substitution=0.3 mmol Lys/g) was
 placed in a 30 ml SPPS reaction vessel. Boc-[C(Z)aeg].sub.10
 -Lys(ClZ)-MBHA resin was assembled by single in situ DCC coupling of the
 first three residues with 0.1 M of BocC(Z)aeg-OH together with 0.1 M DCC
 in 10 ml 50% DMF/CH.sub.2 Cl.sub.2 ("Synthetic Protocol 9") and by single
 in situ DIC coupling of the remaining seven residues with 0.1 M of
 BocC(Z)aeg-OH together with 0.1 M DIC in 10 ml 50% DMF/CH.sub.2 Cl.sub.2
 ("Synthetic Protocol 10"). All the coupling reactions were allowed to
 proceed overnight. The synthesis was monitored by the ninhydrin reaction,
 which showed close to quantitative incorporation of all residues. During
 the synthesis, portions of the shorter fragments H-[C(Z)aeg].sub.5
 -Lys(ClZ)-MBHA resin, H-[C(Z)aeg].sub.6 -Lys(ClZ)-MBHA resin,
 H-[C(Z)aeg].sub.7 -Lys(ClZ)-MBHA resin, H-[C(Z)aeg].sub.8 -Lys(ClZ)-MBHA
 resin, and H-[C(Z)aeg].sub.9 -Lys(ClZ)-MBHA resin were taken out for HF
 cleavage.
 (b) Cleavage, Purification, and Identification of H-[Caeg].sub.5
 -Lys-NH.sub.2
 The protected Boc-[C(Z)aeg].sub.5 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 10.8 mg of crude material upon HF
 cleavage of 60.1 mg dry H-[C(Z)aeg].sub.5 -Lys(ClZ)-MBHA resin.
 (c) Cleavage, Purification, and Identification of H-[Caeg].sub.6
 -Lys-NH.sub.2
 The protected Boc-[C(Z)aeg].sub.6 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 13.4 mg of crude material upon HF
 cleavage of 56.2 mg dry H-[C(Z)aeg].sub.6 -Lys(ClZ)-MBHA resin.
 (d) Cleavage, Purification, and Identification of H-[Caeg].sub.8
 -Lys-NH.sub.2
 The protected Boc-[C(Z)aeg].sub.8 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 16.8 mg of crude material upon HF
 cleavage of 65.6 mg dry H-[C(Z)aeg].sub.8 -Lys(ClZ)-MBHA resin.
 (e) Cleavage, Purification, and Identification of H-[Caeg].sub.10
 -Lys-NH.sub.2
 The protected Boc-[C(Z)aeg].sub.10 -Lys(ClZ)-MBHA resin was treated as
 described in Example 27c to yield about 142.4 mg of crude material upon HF
 cleavage of 441 mg dry H-[C(Z)aeg].sub.10 -Lys(ClZ)-MBHA resin.
 EXAMPLE 116
 Solid-Phase Synthesis of H-[Taeg].sub.2 -Caeg-[Taeg].sub.2
 -Caeg-[Taeg].sub.4 -Lys-NH.sub.2
 (a) Stepwise Assembly of Boc-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.2
 -C(Z)aeg-[Taeg].sub.4 -Lys(ClZ)-MBHA Resin
 About 0.3 g of wet H-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.4 -Lys(ClZ)-MBHA
 resin from the earlier synthesis of Boc-[Taeg].sub.5 -C(Z)aeg-[Taeg].sub.4
 -Lys(ClZ)-MBHA resin was placed in a 5 ml SPPS reaction vessel. After
 coupling of the next residue five times, a total incorporation of
 BocC(Z)aeg of 87% was obtained. The five repeated couplings were carried
 out with 0.18 M BocC(Z)aeg-OPfp in 2 ml of TFE/CH.sub.2 Cl.sub.2 (1:2,
 v/v), 2 ml of TFE/CH.sub.2 Cl.sub.2 (1:2, v/v) , 2 ml of TFE/CH.sub.2
 Cl.sub.2 (1:2, v/v) with two drops of dioxane and two drops of DIEA (this
 condition gave only a few per cent coupling yield), 2 ml of TFE/CH.sub.2
 Cl.sub.2 (1:2, v/v) plus 0.5 g phenol, and 1 ml of CH.sub.2 Cl.sub.2 plus
 0.4 g of phenol, respectively. The two final Taeg residues were
 incorporated close to quantitatively by double couplings with 0.25 M
 BocTaeg-OPfp in 25% phenol/CH.sub.2 Cl.sub.2. All couplings were allowed
 to proceed overnight.
 (b) Cleavage, Purification, and Identification of H-[Taeg].sub.2
 -Caeg-[Taeg].sub.2 -Caeg-[Taeg].sub.4 -Lys-NH.sub.2
 The protected Boc-[Taeg].sub.2 -C(Z) aeg-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.4
 -Lys(ClZ)-MBHA resin was treated as described in Example 27c to yield
 about 7 mg of crude material upon HF cleavage of 80.7 mg dry
 H-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.2 -C(Z)aeg-[Taeg].sub.4 -Lys(ClZ)-MBHA
 resin. The crude product was purified to give 1.2 mg of H-[Taeg].sub.2
 -Caeg-[Taeg].sub.2 -Caeg-[Taeg].sub.4 -Lys-NH.sub.2 (&gt;99.9% purity).
 EXAMPLE 117
 Synthesis of a PNA with Two Anti Parallel Strands Tied Together
 Synthesis of
 H-[Taeg]-[Taeg]-[Taeg]-[Gaeg]-[Taeg]-[Taeg]-[Taeg]-[6-AHA]-[aeg]-[6-AHA]-[
 Taeg]-[Taeg]-[Taeg]-[Aaeg]-[Taeg]-[Taeg]-[Taeg]-LYS-NH.sub.2
 (6-AHA=6-aminohexanoic acid) (FIG. 17)
 The protected PNA was assembled onto a Boc-Lys(ClZ) modified MBHA resin
 with a substitution of approximately 0.30 mmol/g. Capping of uncoupled
 amino groups was only carried out before the incorporation of the
 BocGaeg-OH monomer. Synthesis was initiated on 1.00 g (dry weight) of
 preswollen (overnight in DCM) and neutralized Boc-Lys(ClZ)-MBHA resin. The
 incorporation of the monomers followed the protocol of Example 42 and
 Example 81. The coupling reaction was monitored by qualitative ninhydrin
 reaction (kaiser test). In case of a positive Kaiser test, the coupling
 reaction was repeated until the test showed no coloration of the beads.
 Final deprotection, cleavage from support, and purification were performed
 according to standard procedures.
 EXAMPLE 118
 Alternative Protecting Group Strategy for PNA-synthesis (FIG. 18)
 (a) Synthesis of Test Compounds
 2-amino-6-O-benzyl purine. To a solution of 2.5 g (0.109 mol) of sodium in
 100 ml of benzyl alcohol was added 10.75 g (0.063 mol) of
 2-amino-6-chloropurine. The mixture was stirred for 12 h at 120 0.degree.
 C. The solution was cooled to room temperature and neutralized with acetic
 acid and extracted with 10 portions of 50 ml of 0.2 N sodium hydroxide.
 The collected sodium hydroxide phases were washed with 100 ml of diethyl
 ether and neutralized with acetic acid, whereby precipitation starts. The
 solution was cooled to 0.degree. C. and the yellow precipitate was
 collected by filtration. Recrystallization from ethanol gave 14.2 g 92% of
 pure white crystals of the target compound. 1H-NMR (250 MHz--DMSO-d6) d
 ppm: 8-H, 7.92; benzyl aromatic, 7.60-7.40; 2NH2, 6.36; benzyl CH2, 5.57.
 (2-amino-6-O-benzyl purinyl)methylethanoate. A mixture of 5 g (0.0207 mol)
 of 2-amino-6-O-benzyl-purine, 30 ml of DMF and 2.9 g (0.021 mol) of
 potassium carbonate was stirred at room temperature. Methyl bromoacetate
 (3.2 g; 1.9 ml; 0.0209 mol) was added dropwise. The solution was filtrated
 after 4 h and the solvent was removed under reduced pressure (4 mmHg,
 40.degree. C.). The residue was recrystallized two times from ethyl
 acetate to give 3.7 g (57%) of the target compound. 1H-NMR (250 MHz,
 DMSO-d6) d ppm: 8-H, 7.93; benzyl aromatic 7.4-7.6; 2-NH.sub.2, 6.61;
 benzyl CH2, 5.03; CH2, 5.59; OCH3, 3.78.
 (2N-p-Toluene sulfonamido-6-O-benzyl purinyl) methyl ethanoate. To a
 solution of 0.5 g (1.6 mmol) of (2-amino-6-O-benzyl purinyl) methyl
 ethanoate in 25 ml methylene chloride was added 0.53 g (1.62 mmol) of
 p-toluenesulfonic anhydride and 0.22 g (1.62 mmol) of potassium carbonate.
 The mixture was stirred at room temperature. The mixture was filtered and
 the solvent was removed at reduced pressure (15 mmHg, 40.degree. C.).
 Diethyl ether was added to the oily residue. The resulting solution was
 stirred overnight, whereby the target compound (0.415 mg; 55%)
 precipitated and was collected by filtration. 1H-NMR (250 MHz, DMSO-d6) d
 ppm: 8-H, 8.97; aromatic 7.2-7.8; benzyl CH2, 5, 01; CH2, 4.24; OCH3,
 3.73; CH3, 2.43.
 (b) Stability of the Tosyl Protected Base-residue in TFA and HF
 The material was subjected to the standard deprotection conditions
 (TFA-deprotection) and the final cleavage conditions with HF. The products
 were then subjected to HPLC-analysis using a 4.mu. RCM 8.times.10 Nova
 pack column and solvents A (0.1% TFA in water) and B (0.1% TFA in
 acetonitrile) according to the following time gradient with a flow of 2
 ml/min.