bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemistry of the Group 1B metals. XVII. Preparation of some gold(I) acetylide complexes containing Group 5 donor ligands: Crystal and molecular structures of Au(C2C6F5)(PPh3)
Authors: Bruce MI , Horn E , Matisons JG , Snow MR
Published: September 2010

Experimentally convenient
syntheses of a series of gold(I) acetylide complexes
containing tertiary phosphines include reactions
between AuCl(PR3) [R3 = Me3,
Ph3, Ph(OMe)2] and alk-1-ynes,
either in diethylamine in the presence of copper(I) halides, or with
methanol/sodium methoxide. Yields are good to
excellent; several compounds are light-sensitive, and react violently with
chlorinated solvents. The crystal structure of Au(C2C6F5)(PPh3)
has been determined. It is monomeric, with almost linear two-coordinate Au:
Au-C 1.993(14), Au-P 2.274(3), C=C 1.197(16) �. Crystals are monoclinic, space
group P21/c, with a
16.104(2), b 8,653(1), c 17.560(3) �, β 112.98(1)�, Z 4;
1761 data with I > 2.5σ(I) were refined to R, Rw = 0.033,
0.034.
Oxidations with lead tetraacetate. V. Oxidations of 1,3-benzoxathioles
Authors: Aromdee C , Cole ER , Crank G
Published: September 2010

2,2-Disubstituted
1,3-benzoxathioles are easily oxidized by lead tetraacetate to a complex
mixture of products. Acetoxylation takes place on the first carbon atom of the
2-alkyl or -cycloalkyl sub- stituent giving acetoxy derivatives. The hetero
ring is also opened yielding ketones, acetoxyketones, a disulfide and polymeric
materials. Oxidation at the sulfur atom appears to be a minor reaction and no
products oxidized in the benzene ring are found.
The reduction of 2-substituted furan derivatives with lithium and ammonia
Authors: Massy-Westropp RA , Warren RFO
Published: September 2010

The reduction of
1-(furan-2'-yl)nonan-1-one with lithium and ammonia in the presence of alcohols
gave 1-(2',3'-dihydrofuran-2'-yl)nonan-1-one as the major product or a mixture
of 1-(tetrahydrofuran-2'-yl)nonan-1-one and tridecane-1,5-diol depending on the
conditions. 1-(Furan-2'-y1)nonyl acetate,
2-(1'-methoxynonyl)furan, 1-(furan-2'-yl)nonan-1-ol, 2-(1',1'-ethylenedioxynonyl)furan
and 2-(pent-1'-eny')furan have also been reduced both in the presence and
absence of an alcohol.
Organophosphorus compounds. XXI. Solvolysis and C3-substitution reactions of some 2,3-Dihydro-1H-1,2-benzazaphosphole 2-oxides and 2-sulfides
Authors: Collins DJ , Drygala PF , Swan JM
Published: September 2010

The solvolysis in D2O/CD3SOCD3
of the 2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole
2-oxides (5a-c), the analogous 2-methyl derivatives (6a-c), and of the 2-methyl-2,3-dihydro-lH-1,2-benzaza-phosphole 2-sulfides (6d)
and (6e) was examined semi-quantitatively by n.m.r. spectroscopy. 1-Methyl-2-phenyl-2,3-dihydro-1
H-1,2-benzazaphosphole 2-oxide (5b)
was subjected to reductive ring-opening reactions, base-catalysed C3-alkylation,
and base-catalysed formation of a 3-benzylidene derivative.
Mutarotation of D(+)-glucose. III. Evidence for cooperative and competitive nucleophilic catalysis by molybdenum(VI) and tungsten(VI) anions
Authors: O'Conner CJ , Bailey AAT
Published: September 2010

The rate of mutarotation of α-D(+)-glucose is subject
to general base catalysis by a variety of oxo anions. The relative magnitudes
of the second-order rate constants are
B4O72->W7O246->Mo7O246- > HCO3->WO42->MoO42-
Catalysis by W7O246- and Mo7O246- is competitive but that by WO42- and MoO42- is
cooperative. A mechanism for catalysis by the polymeric anions is proposed
which involves ion-pair formation between the anion and the conjugate acid of
glucose. Specifically oriented aquation sheaths about
the charged ions cause them to act as enhanced nucleophiles
in the rate-determining step to form the aldehyde
intermediate. Activation parameters support this model.
Collision-induced dissociations of negative ions. α-Dicarbonyl parent negative ions
Authors: Bowie JH , Blumenthal T , Laffer MH , Janposri S , Gream GE
Published: September 2010

α-Dicarbonyl
compounds form stable parent negative ions by capture of low-energy electrons.
The parent negative ions undergo a variety of collision induced dissociations,
the most characteristic being β cleavage to a carbonyl group, i.e. see diagram in paperCyclic α-dicarbonyl parent negative ions may also eliminate
molecules of carbon monoxide, for example the fragmentations M- → [M-(R +
CO)]- M- →[M - (R-2CO)]- and M- → [M-2CO]- occur in a
number of cases.
The crystallographic characterization of an unusual chemical reversal of photoisomerization
Authors: Cornforth SJ , Patrick VA , White AH
Published: September 2010

lmines formed from
pinacolone and primary amines could be acylated by acid chlorides or anhydrides
to products hydrolysable to 1,3-diones. Renzoyl chloride with pinacolone
benzylinline gave
3-(N-benzoyl-N-benzylamino)-4,4-dimethyl-1-phenylpent-2-en-1-one, both
geometrical isomers of which were prepared. The yellow Z isomer was converted
into the colourless E isomer on exposure to daylight and this change was
reversed by brief treatment of the E isomer with aqueous ethanolic alkali. The
Z and E isomers have been characterized crystallographically. The E isomer is
monoclinic, C2/c, a 10.241(4), b 17.199(6), c 25.495(9) �, β 100.45(3)�, Z = 8; R was 0.052 for 1947
'observed' reflections. The Z-isomer is orthorhombic, P212121,
a 18.24(1), b 15.60(l), c 7.871(4) �,
Z = 4; R was 0.061 for 902 'observed' reflections.
The reaction of N-dichloromethylene-N,N-dimethylammonium chloride (Viehe's salt) with thiophenols and phenols: a synthesis of unsymmetrical diaryl carbonates
Authors: Copeland C , Stick RV
Published: September 2010

The reaction of N-dichloromethylene-N,N-dimethylammonium chloride (Viehe's salt) with various thiophenols
and phenols is reported. The resulting intermediate salts are generally
transformed by water or sodium hydrogen sulfide to thiocarbonates
and thiocarbamates. An efficient synthesis of unsymmetrical
diaryl carbonates is discussed.
Metabolites of the marine red alga Laurencia thyrsifera. III
Authors: Blunt JW , Lake RJ , Munro MHG
Published: September 2010

A series of halogenated
cyclic ethers have been isolated from the New Zealand red alga Laurencia thyrsuera.
Their structures and stereochemistries are presented.
The stereochemistry of (+)-intricenyne is
established.
Some semi-empirical molecular orbital studies of the origin of conformational preferences for free S2O42- and N2O4
Authors: Harcourt RD , Smith BJ , Marsden CJ
Published: September 2010

The results of some
semi-empirical MO-CI calculations of the barriers to rotation around the S-S
and N-N bonds of S2O42- and N2O4
are reported. The calculated barriers are expressed in terms of atomic, cis O-O
overlap, coulombic repulsion and exchange contributions.
The barrier analysis for N2O4 shows that cis O-O overlap
stabilizes the planar relative to the skew conformer, whereas for free S2O42-,
reduced coulombic repulsions stabilize the trans
conformer relative to the eclipsed. Some CNDO/2 estimates of the rotation
barrier for S2O42- are also reported.
Preparation of t-Butyl 2-(Phenylthiomethyl)propenoate, t-Butyl 3-(Phenylthio)-2-(phenylthiomethyl)propenoate and related compounds
Authors: Haynes RK , Katsifis A , Vonwiller SC
Published: September 2010

The preparation of t-butyl
2-(phenylthiomethyl)propenoate,
t-butyl and methyl 3-(phenylthio)-2-(phenylthiomethyl)propenoate, the corresponding carboxylic acids, and
3-(phenylthio)-2-(phenyl- sulfinylmethyl)propenoate
from 3-bromo-2-(bromomethyl)propionic
acid is described.
Synthetic applications of intramolecular insertion in arylcarbenes. VII. Aryl-substituted benzocycloalkenylidenes
Authors: Crow WD , Engkaninan-Low U , Pang YT
Published: September 2010

A series of benzo-fused cyclic carbenes,
bearing suitably located alkoxy substituents in the
phenyl ring, has been generated in the gas phase and pyrolysed
at 250�/0.002-0.40 mm. In all cases, carbene
insertion into the adjacent C-H bond (Bamford-Stevens
insertion) occurs, either exclusively or predominantly, with up to 35% 1,5 C-H
insertion in the alkoxy side chain to form peri-fused
tricyclic heterocycles. These results are rationalized in terms of geometrical
and electronic effects.
Synthesis of dihydroisotryptamines
Authors: Gellert E , Wong O
Published: September 2010

To enable exploration of
the physiological activity of isotryptamine derivatives, a number of 1,3-di-hydroisotryptamines,
isomers of known tryptamine derivatives possessing significant physiological
activity, were synthesized for the first time. Ring-substituted
1-nitrosonaphthalen-2-ols on tosylation and alkaline treatment gave the
appropriate (Z)-3-(2'-cyanopheny1)propenoic acids, and by hydration,
cyclization and ring-opening these acids were converted into
(3'-oxo-1',3'-dihydroisoindol-1'-yl)- acetic acids. Fusion of these products
with ureas yielded the corresponding (3'-oxodihydroisoindol-1'-yl)acetamides,
which, on simultaneous reduction of the amide and lactam functions by diborane,
yielded 1,3-dihydroisotryptamines. Some features of their n.m.r. spectra are
also discussed.
Synthesis and properties of optically active podands incorporating sulfoxide functionality
Authors: Raguse B , Ridley DD
Published: September 2010

A series of optically
active podands incorporating ether and chiral
sulfoxide functionality have been synthesized. The podands
formed relatively strong complexes with protonated
amines. Where racemic guests were used, the diastereoisomeric complexes were identified
in solution by 1H n.m.r. spectroscopy but the energies of formation
of these complexes were too similar to afford optical resolution of guests. The
podands influenced the stereochemistry of
t-butoxide-catalysed additions of methyl 1-oxoindane-2-carboxylate to methyl
vinyl ketone, but stereoselectivities observed were
low.
The chemistry of pyrrolic compounds. LVII. The oxidative cyclization of derivatives of 1,19-dideoxybilenes-b
Authors: Clezy PS , Thuc Lv
Published: September 2010

A study of the oxidative
cyclization of 13C-labelled bilenes-b
substituted with a methyl group at one terminal position and a formyl
equivalent at the other, e.g. (1), has clearly established that the methyl
group provides the carbon atom to complete the ring system. The basic mechanism
of this reaction is discussed.
The anodic oxidation of carbon monoxide on gold in acid solutions
Authors: Farrugia TR , Fredlein RA
Published: September 2010

The anodic oxidation of
carbon monoxide on gold was studied in the oxide-free potential region, linear
sweep voltammetry being used to minimize electrode
poisoning. Only when pco
< c. 0.3 atm or when the reaction was inhibited by
impurities were the plots of i against square root of
scan rate linear. In other cases, i attained constant
values at high scan rates; this is interpreted, together with other evidence,
as due to the adsorption of CO prior to the start of the scan. Good Tafel plots were obtained under conditions where i was independent of scan rate, and the kinetic parameters
are shown to be consistent with the Gilman reactant-pair mechanism. In the
potential region of oxide formation on gold, the steady-state oxidation of CO
proceeded with the formation of colloidal gold. The mechanism in this potential
region was not investigated.
Positional selectivity of the methylation of 5-substituted tetrazolate anions
Authors: Spear RJ
Published: September 2010

The methylation of a series
of 15 sodium 5-substituted tetrazolates using iodomethane in acetone/water (4 : 1) has been studied. The
reaction yields both 1- and 2-methyl products, and the ratio of these products
is discussed in terms of the nature of the 5-substituent. Electronic and steric
effects dominate the reaction pathway; both increased substituent electro negativity
and steric bulk lead to predominant methylation at N2. Sodium
5-ethoxycarbonyltetrazolate (3n) goes against this trend and an intermediate is
proposed where the incoming electrophile is associated with the ester carbonyl
group.
Crystal structure of 3-Phenylbenzothiazolo[2,3-b]thiazol-1-io-2-olate
Authors: Raston CL , White AH
Published: September 2010

The crystal structure of
the title compound, C15H9NOS2, has been
determined by single-crystal X-ray diffraction methods at 295 K, being refined
to a residual of 0.057 for 2006 independent 'observed' reflections. Crystals
are monoclinic, P21/n, a
13.467(5), b 9.426(3), c 20.680(9) �, β 107.38(3)�, Z = 8.
The two molecules are substantially planar; close intermolecular contacts as
well as bond-order distributions are strongly suggestive of negative charge
localization on the oxygen atoms with positive charge density localized in the
S-C-S string.
Systemic Fungicides. The Synthesis of Pyrazolo[1,5-a]pyrimidine Analogues of Carboxin
Authors: Huppatz JL
Published: September 2010

The synthesis of a series of pyrazolo [1,5-a] pyrimidine derivatives, structural analogues of the systemic fungicide carboxin, is described. A common intermediate incorporating structural features desirable for fungicidal activity, N-phenyl-3(5)-amino-5(3)-methylpyrazole-4- carboxamide (6), was used to prepare pyrazolo [1,5-a] pyrimidines variously substituted in positions 5 and 7 of the ring system. Bromination of N-phenyl-2-methylpyrazolo[1,5-a]pyrimidine-3-carboxamide (8) occurred preferentially in the phenyl ring and the 6-bromo derivative was prepared by bromination of the corresponding 3-ethoxycarbonyl derivative (24). Attempted nitration of the ester (24) resulted in displacement of the ethoxycarbonyl substituent by a nitro group. The simplest pyrazolo [1,5-a] pyrimidine (8) showed a high level of fungicidal acitvity in fungal growth assays of Basidiomycete species, but compounds substituted in the pyrimidine ring were inactive.
A simple method of polyamine purification
Authors: Stapleton IW
Published: September 2010

A simple procedure for the large-scale purification of commercial polyethyleneamines (H2N[CH2CH2NH]nH where n = 2-5) is described in which the per- tosylate salt separates as a crystalline solid from aqueous solution. The salts require no further purification except for pentaethylenehexamine (n = 5), which requires recrystallization from water. The free bases are regenerated from the tosylate salt by an anion-exchange resin.
Substitutent Effects in Non-Aromatic Nitrogen Heterocycles: Alkaline Hydrolysis of Methyl N-Methyl (oxo)dihydropyridinecarboxylates and Diaza Analogues
Authors: Deady LW
Published: September 2010

Ester hydrolysis studies on some isomeric methoxycarbonyl derivatives of N-methylpyridin-2- and 4-ones show that reaction rates are affected by the relative positions of CO2Me, =O and NMe functions in ways which could not be predicted. However, from limited result for analogous pyrimidine derivatives, it seems that reactivity in these polyfunctional compounds can be predicted from the pyridine data by assuming additivity of effects.
Central Nervous System Active Compounds. XV. 2-Arylisoxazol-5(2H)-ones
Authors: Hung TV , Janowski WK , Prager RH
Published: September 2010

Ethyl 5-oxo-2,5-dihydroisoxazole-4-carboxylate has been treated with a number of chlorinated heterocycles to yield the corresponding substitution products: ethyl 2-(isoquinolin-1-yl)-5-oxo-2,5-dihydroisoxazole-4-carboxylate, ethyl 5-oxo-2-(quinolin-2-yl)-2,5- dihydroisoxazole-4-carboxylate, ethyl 5-oxo-2-(purin-2-yl)-2,5- dihydroisoxazole-4-carboxylate, ethyl 5-oxo-2-(pyrimidin-2-yl)-2,5-dihydroisoxazole-4-carboxylate, ethyl 2-(6-chlorpyridazin-3-yl)-5-oxo- 2,5-dihydroisoxazole-4-carboxylate, ethyl 2-(benzothiazol-2-yl)-5-oxo- 2,5-dihydroisoxazole-4-carboxylate, 2- and 6-(4-ethoxycarbonyl-5-oxo-2,5-dihydroisoxazol-2-yl)pyridine-3-carboxylic acid, ethyl 5-oxo- 2-(2-phenylquinazolin-4-yl)-2,5-dihydroisoxazole-4-carboxylate and ethyl 2-(2,4-diaminotriazin-2-yl)-5-oxo-2,5-dihydroisoxazole-4- carboxylate . The compounds generally cause loss of motor control in mice, but are relatively toxic.
Micellar Effects on the Formation of the 1,3,5-Trinitrobenzene-Cyanide Complex in Water
Authors: Gan L
Published: September 2010

The anionic σ-complex from cyanide ion and 1,3,5-trinitrobenzene in water was stabilized by cationic micelles. The binding of counter ions to the micellar head groups in hexadecyl-trimethylammonium cyanidefollowed a distribution model with the counter ion binding constant KCN = 1400 mol-1 dm3. The bromide-cyanide ion exchange constant, KCNBr, was equal to 1.28. These results rendered further support to the general applicability of the distribution model.
Preparation and Crystal Structure of the Unusual Palladium(II) Chloride/Optically Active Sulfoxide Complex: µ-[(R,R)-1,5-Bis{o-(p-toluenesulfinyl)phenoxy}-3-oxapentane]-bis(µ-chloro)-dichlorodipalladium Dichloromethane Solvate, [Pd2Cl4(C30H30O5S2)].(CH2Cl2)2
Authors: Hambley TW , Raguse B , Ridley DD
Published: September 2010

A complex between palladium(II) chloride and the optically active podand , (S,S)-1,5-bis[o-(p- toluenesulfinyl ) phenoxy ]-3-oxapentane, has been prepared and is shown to contain two equivalents of palladium(II) chloride to one equivalent of the podand. Crystal structure analysis shows each of the sulfur atoms in the sulfoxide groups is coordinated to a palladium atom, and the palladium atoms are also linked through chloride bridges. Crystal data: a 14.878(2), b 17.226(3), c 8.178(1) Ǻ, β 103.30(1)°; P21; Z 2.
Stereochemical Aspects of Aldehyde Additions to Cyclohex-2-Enylstannanes
Authors: Young D , Kitching W
Published: September 2010

Cyclohex-2-enylation of aldehydes, mediated with boron trifluoride etherate, involves γ-equatorial approach of the presumed aldehyde-Lewis acid adduct (RCHO-BF3), irrespective of starting stannane stereochemistry. Marginal threo selectivity characterizes homoallyl alcohol formation from benzaldehyde, whereas alkanals react with high erythro selectivity, so that 1-(1′-hydroxyalkyl)cyclohex-2-enes in this diastereomeric form are available based on allyltin chemistry.
Crystal-Structures of cis-(N-Base)Chlorobis-(Ethane-1,2-Diamine)Cobalt(III) Dichloride (N-Base = Ammonia, Pyridine)
Authors: Harrowfield JM , Skelton BW , White AH , Wilner FR
Published: September 2010

The crystal structures of the two title compounds, cis-[Co(en)2(NH3) Cl ] Cl2, (1), and cis-[Co(en)2( py ) Cl ]Cl2.H2O, (2), have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by full-matrix least-squares techniques to residuals of 0.025 and 0.036 for 1744 and 3243 independent 'observed' reflections. Crystals of (1) and (2) are monoclinic, P21/c, Z = 4. For (1), a 7.499(1), b 11.986(2), c 14.325(3)Ǻ, β 111.45(1)°; for (2), a 7.617(2), b 12.866(3), c 16.561(5), β 97.33(2)°. Both complexes are racemates with cation conformations Δ( δ,λ ), (1), and Δ( λ,λ ), (2). The structure determinations suggest that variations in the rate of base hydrolysis of these complexes and their imidazole analogue may be correlated with the degree of steric crowding associated with the introduction of the monodentate nitrogen base into the coordination sphere.
On the Electrochemical-Behavior of Pyrylium Ions at the Mercury-Electrode. II. Aromatically Substituted Ions in Acetonitrile
Authors: Garrard WNC , Thomas FG
Published: September 2010

The electrochemical behaviour of the 2,4,6-triphenylpyrylium ( tpp +) and 7-phenyl-5,6,8,9-tetrahydrodibenzo[ c,h ] xanthylium (thx+) ions in acetonitrile in the presence of 0.1 M tetrabutylammonium perchlorate is reported. The reduction of both ions proceeds by two, one-electron steps. The initial product of the first reduction is the corresponding radical, which may dimerize to give isomeric bipyrans in the case of tpp + or a phenyl-phenyl or phenyl- pyranyl dimer in the case of thx+. The corresponding anions are the initial products of the second reduction step. The tpp - anion reacts with tpp + to give the bipyran while the thx- anions appear to undergo polymerization reactions with thx+. Both tpp + and thx+ and their reduction products are adsorbed at the mercury electrode. In the adsorbed state thx+ forms one of two surface phases depending on the potential, one with the molecules in a flat orientation and the other, a condensed phase, with vertically oriented molecules. Perchlorate ions are considered to be co-adsorbed with the cations.
Acetal Formation Facilitated in 2-Hydroxyaryl Aldehydes by Intramolecular Acyl Group Transfer
Authors: Liepa AJ , Liepa AJ , Morton TC , Morton TC
Published: September 2010

Convenient preparations of synthetically useful acetals, a dithioacetal and an oxathiolan from the 2-acyl derivatives of 2-hydroxyaryl aldehydes under basic conditions are described. The mildness of the reaction conditions is illustrated by the formation of an ethoxycarbonyl -substituted dioxolan . The reaction is dependent upon an intramolecular acetyl group transfer and the mechanism of the reaction is discussed. Some broader implications of this type of acyl transfer are discussed.
Naturally-Occurring Dibenzofurans. X. A New Synthesis of Di-O-Methylstrepsilin
Authors: Giles RGF , Sargent MV
Published: September 2010

A new synthesis of 4,8-dimethoxy-10-methylisobenzofuro[5,4- b]benzofuran-3(1H)-one (di-O-methylstrepsilin) (2), a derivative of the lichen dibenzofuran strepsilin (1), is described.
Synthesis and Properties of Optically Active Coronands Incorporating Sulfoxide and Sulfoximine Functionality
Authors: Hambley TW , Hambley TW , Raguse B , Raguse B , Ridley DD , Ridley DD
Published: September 2010

A number of optically active coronands incorporating sulfoxide and sulfoximine functionality have been prepared and their association constants for complexes with alkali metal and ammonium picrates have been measured. Some of these complexes have association constants greater than 70000 1. mol-1 with selectivity for lithium and sodium cations, but no stereoselectivity has been observed for complexes with racemic ammonium guests. The X-ray crystal structure of one of the sulfoxide coronands is reported.
Spectrophotometric and Electron Spin Resonance Studies on Acetylacetonato(N,N,N',N'-Tetra-Methylethylenediamine)Copper(II) Tetraphenylborate in Various Solvents
Authors: Lim YY
Published: September 2010

1 : 1 equilibrium constants for the Lewis acid-base interaction between acetylacetonato- (N, N, N', N'- tetramethylethylenediamine )copper(II) tetraphenylborate and tetrahydrofuran, pyridine, ethylacetate and N, N- dimethylformamide were obtained at 298 K in 1,2-dichloroethane by u.v .-visible spectrophotometry . The optical absorption maxima, D, of the mixed-chelate copper(II) complex in various donor solvents which decrease as the axial interaction increases were also measured and it was found that no linear correlation exists between C (cm-l) and the solvent donor number. Isotropic hyperfine coupling constants of 63,65Cu, Aiso, and isotropic g values, giso were obtained in various solvents. In general, Aiso decreases but giso increases as the axial interaction increases. The coefficient, α, of the dx2-y2 orbital in the ground state molecular orbital (B1g) was found to decrease with increasing axial interaction. The frozen solution e.s.r. spectra als ; gave α values similar to those obtained from the solution spectra. The relationship g?> g? was found in all solvents, indicating the presence of elongated tetragonal symmetry.
The Iodine Propanenitrile Water-System. Effects of Added Salts on Distribution Coefficient and Conductivity
Authors: Avraamides J
Published: September 2010

Distribution coefficients for iodine in the propanenitrile-water solvent system were measured as a function of the nature and concentration of various added metal halides. BothNaCl and KI at concentrations between 1 and 3 M had a positive effect on the distribution coefficient. Zinc halides, particularly zinc iodide, tended to lower the distribution coefficient significantly and also raised the conductivity of the organic phase. These studies suggest that the two-phase solvent system is suitable for application in a zinc-iodine battery.
Improved Procedure for Conversion of Penicillin V Into Monocyclic β-Lactams
Authors: Davis M , Wu WY
Published: September 2010

Improved procedures for the preparation of the Kamiya compound (3 R,4R)-4-(benzothiazol-2′-yldithio)-3-phenoxyacetamidoazetidin-2-0 (6) from penicillin V (1) are described. A novel feature is ozonolysis, near room temperature, in aqueous methanol in the presence of pyridine or a trace of manganese dioxide.
Reproducibility of Interlaboratory Tritium N.M.R. Results and Influences of Alkyl Substituents on Chemical Shifts of Aromatic Tritons in Alkylbenzenes
Authors: Odell AL , Martin RW , Larsen DO , Long MA , Garnett JL , Than C , Williams PG
Published: September 2010

Chemical shifts for aromatic tritons have been varying by up to 0.1 ppm when measured in different laboratories. This is attributable to solvent effects. For truly identical solvents this error is shown to reduce to about 0.002 ppm (less than the digitization error). New chemical shift values for aromatic tritons in a series of alkylbenzenes are reported.
Three New Lichen Depsidones
Authors: Elix JA , Gaul KL , James PW , Purvis OW
Published: September 2010

The depsidones α- acetylconstictic acid (5-acetoxymethyl-1,4-dihydroxy-10-methoxy-8-methyl-3,7-dioxo-1,3-dihydro-7 H- isobenzofuro [4,5- b][l,4] benzodioxepin-ll-carbaldehyde ) (6), substictic acid (1,4-dihydroxy-10-methoxy-8-methy1-3,7-dioxo- 1,3-dihydro-7 H- isobenzofuro [4,5-b][1,4]benzodioxepin-11-carbaldehyde) (7) and conphysodalic acid (9-acetoxymethyl-3,8-dihydroxy-4-hydroxymethyl-1,6-dimethyl-11-oxo-11 H- dibenzo [ b,e ][l,4]dioxepin-7-carboxylic acid) (12) have been identified in lichens and characterized.
An ab initio Study of the Equilibrium Structures of Prop-2-ynamine (Propargylamine) and the Transition Structures Connecting Them
Authors: Riggs NV
Published: September 2010

Optimization with the 3-21G and 3-21G(N*) basis sets finds, in agreement with previous ab initio studies and the experimental result, the anti conformation of prop-2-ynamine to be of lowest energy and, after zero-point vibrational -energy ( Ezpv ) corrections, the gauche form to lie 11 kJ mol-l higher; by vibrational analysis, both are confirmed as equilibrium structures. The synform was not able to be optimized with the 3.21G basis set but, with the 3-21G(N*) basis set, is found to lie 8.6 kJ mol-1 (after Ezpv corrections) above the gauche form, and is shown by vibrational analysis to be a transition structure connecting enantiomeric gauche forms by internal rotation about the N-C bond. The transition structure connecting gauche and anti forms by internal rotation lies 6.3 kJ mol-1 (after Ezpv corrections) above the gauche form, and the transition structure for inversion at the nitrogen atom lies 31.1 kJ mol- l (after Ezpvcorrections) above the anti form.
Stereochemical and Mechanistic Aspects of the Aprotic Conjugate Addition Reactions of the Carbanions of Octenyl Sulfides and Octenyl Thiocarbamates With 4-Tert-Butoxycyclopent-2-Enone in the Presence of Hexamethylphosphoric Triamide
Authors: Binns MR , Haynes RK
Published: September 2010

The carbanions of (E)- and (Z)-1-(pheny1thio)oct-2-ene, (E)-1-(methy1thio)- and 1-(t-butyl- thio )oct-2-ene, N,N-dimethyl S-[(E)-oct-2-enyllthiocarbamate and (E)-oct-2-enyl benzothiazole undergo conjugate addition to 4-t-butoxycyclopent-2-enone in the presence of hexamethyl - phosphoric triamide ( hmpa ) in tetrahydrofuran at -70� to give as predominant products diastereomeric mixtures of syn and anti allylic sulfides arising from reaction through C1 of the octenyl carbanions. Also formed in some cases are small amounts of diastereomeric mixtures of syn and anti vinylic sulfides arising from reaction through C3 of the octenyl carbanions. In the absence of the hmpa, carbonyl addition is the major reaction pathway of the carbanions of each of the (E)- and (Z)- octenyl thiocarbamates. The constitutions and stereostructures of all the products have been established through chemical shift and coupling constant correlations of their IH n.m.r. data obtained at 400 MHz. The relative proportions of the regioisomeric allylic and vinylic sulfides are dependent both upon the nature of the non-allylic substituent attached to the sulfur atom, and the geometry of the double bond in the starting octenyl sulfide. While there is no apparent connection between the electronic properties or sizes of the non-allylic substituent and the diastereomer ratios of the allylic and vinylic sulfides, it is noted that the (2)-(phenylthio) octene delivers an allylic sulfide mixture enriched in the syn isomer. It is concluded that the carbanions are configurationally stable at-70� and that the configurations of the vinylic sulfides reflect the configurations of the carbanions from which they are derived. It is also concluded that the reactions proceed under orbital control, as this best accounts for the formation of the vinylic sulfides and is in accord with the results of STO-3G calculations carried out on a series of sulfur-bearing allylic carbanions . The likely angle of attack of the carbanions on the enone system is briefly discussed in terms of a published model relating to the attack of a simple nucleophile on an electrophilic double bond.
Metal Phenoxyalkanoic Acid Interactions. XXV. The Crystal Structures of (2-Formyl-6-Methoxyphenoxy)Acetic Acid and Its Zinc(II) Complex and the Lithium, Zinc(II) and Cadmium(II) Complexes of (2-Chlorophenoxy)Acetic Acid
Authors: Oreilly EJ , Smith G , Kennard CHL , Mak TCW
Published: September 2010

The crystal structures of (2-formyl-6-methoxyphenoxy)acetic acid (1), diaquabis [(2-formyl-6-methoxyphenoxy) acetato ]zinc(11) (2), tetraaquabis [(2-chlorophenoxy) acetato ]zinc(11) (3), triaquabis [(2-chlorophenoxy) acetato ]cadmium(11) dihydrate (4) and lithium (2-chloro- phenoxy )acetate 1.5 hydrate (5) have been determined by X-ray diffraction. The acid (1) forms centrosymmetric hydrogen-bonded cyclic dimers [O…0, 2.677(6) �] which are non-planar. Complex (2) is six-coordinate with two waters [Zn- Ow , 1.997(2) �] and four oxygens from two asymmetric bidentate carboxyl groups [Zn-O, 2.073, 2.381(2) �] completing a skew trapezoidal bipyramidal stereochemistry. Complex (5) is also six-coordinate but is octahedral, with two trans-related unidentate carboxyl oxygens [mean Zn-O, 2.134(9) �] and four waters [mean Zn-O, 2.081(9) �]. The seven-coordinate complex (4) has crystallographic twofold rotational symmetry relating two :symmetric bidentate acid ligands [ Cd -O, 2.26, 2 48(:) �] and two waters [ Cd -O, 2.34(2) �] while the third water lies on this axis [ Cd -O, 2.27(2) �]. In contrast to the monomers (2)-(4), complex (5) is polymeric with tetrahedral lithium coordinated to one water and three carboxylate oxygens [mean Li-0, 1.95(1) �]. The essential conformation of the free acid is retained in complexes (2), (3) and (4) but in (5), it is considerably changed.
Selectivity of the Hydrogenation of 2',4',7-Tribenzyloxyisoflavone
Authors: Visser FR , Lane GA
Published: September 2010

Hydrogenation of 2',4',7-tribenzyloxyisoflavone (1) on a palladium/carbon catalyst gave nine products ranging from 4',7-dibenzyloxy-2'-hydroxyisoflavone (7) to 3,9-dihydroxypterocarpan (demethylmedicarpin ) (5) and 2',4',7-trihydroxyisoflavan (6), depending on the conditions. The benzyl groups of partially debenzylated products were located by 1H n.m.r.COSY experiments and chemical shift patterns.
Studies in the Cycloproparene Series: Approaches to Cyclopropaheteroarenes
Authors: Buckland SJ , Halton B , Stanovnik B
Published: September 2010

Photolysis of the pyrazolopyridazines (3) results in the loss of nitrogen. The resultant diradicals (5) do not close to the cyclopropa [d]pyridazines (4) but undergo 1,4-hydrogen transfer to afford the 8-(2'-propenyl)pyridazines (6) instead. In the presence of trapping agents diradicals (5)give ethers (7) with methanol, epoxycyclohepta [d]pyridazines (8) with furan, and the 1,4- and 1,2-addition products (16) and (17) respectively, with butadiene. The formation of (8) and (16)provides the first examples of 1,4-addition of a 1,3-diradical to a diene.
The Chloro and Bromo Complexes of Iridium(III) and Iridium(IV). III. The Crystal-Structures of K3[IrCl6] and Cs2[IrCl5H2O] and Interpretation of the N.Q.R. Data of Chloroiridates(III)
Authors: Coll RK , Fergusson JE , Penfold BR , Rankin DA , Robinson WT
Published: September 2010

The crystal structure of K3[IrCl6] (monoclinic, P21/c, a 1250.0, b 742.3, c 1183.3, Ir-Cl range 235.2-237.3 pm) has been redetermined , and the crystal structure of Cs2 [IrCl5H2O] [orthorhombic, C mcm , a 737.2, b 1728.3, c 801.4 pm, Ir-Cl (mean) 243.3 pm] has been determined. Results of an earlier n.q.r . Study of hexachloroiridates (111) have been interpreted on the basis of their known structures.
Benzannulated Isobenzofurans
Authors: Moursounidis John , Wege Dieter
Published: September 2010

A number of arynes, generated by treatment of haloarenes with sodium or potassium amide
in tetrahydrofuran, were trapped with furan. The resulting dihydro epoxy arenes were
converted into the following annulated isobenzofuran derivatives by using reverse Diels-Alder
methodology: naphtho[l,2-clfuran, phenanthro[9,10-elfuran, pyreno[l,2-elfuran, pyreno[3,4-
elfuran, anthra[l,2- elfuran, phenanthro[l,2- clfuran and phenanthro[3,4- elfuran. Bimolecular
rate constants for the addition of maleic anhydride to these furans were measured, and were
correlated with the Herndon structure count. Addition of arynes to selected members of this furan
series yielded adducts which were deoxygenated to afford polycyclic aromatic hydrocarbons.
A Simple Model for the Mean and Difference of NH-Stretching Frequencies for NH2 Groups, and Its Application to Results of Some ab initio Vibrational-Frequency Calculations
Authors: Riggs NV , Radom L
Published: September 2010

The expression for the sum of the eigenvalues of the 2×2 GF matrix for two interacting NH bonds suggests that the mean NH-stretching frequency for an NH2 group should be closely proportional to ( Σf )½, where Σf is the sum of the two corresponding force constants. Ab initio results for the NH2 groups in various conformations of ethanamine , hydrazine and 1,1-dimethylhydrazine confirm such constancy to within 0.1%. The corresponding expression for the difference of the eigenvalues suggests, counterintuitively, that the difference of NH-stretching frequencies for an NH2 group in a given molecular system should also be largely proportional to ( Σf )½ and, except for the gauche conformation of 1,1-dimethylhydrazine, ab initio results for the above molecules support this suggestion to within �14 cm-1. In the exceptional case, the difference of NH-stretching force constants makes a much larger than usual contribution. Relative values of the force constants for various molecular species may be interpreted in terms of the relative geometries and effects of donation of lone-pair electrons at an adjacent centre into antibonding N-H orbitals at the given centre.
Reaction of N-Benzoyl-2-bromoglycine Methyl Ester With Deprotonated Nitroalkanes: Synthesis of β-Nitro and α,β-Dehydro Amino Acid Derivatives
Authors: Burgess VA , Easton CJ
Published: September 2010

N-Benzoyl-2-bromoglycine
methyl ester (1) reacted with the alkyl nitronates (2a-e) to give the corresponding β-nitro amino acid derivatives (4a-e). Elimination reactions of (4a-d) afforded the α,β-dehydro amino acid derivatives (5a-d). Treatment of the β- nitrovaline derivative (4b) with tributyltin hydride gave the valine derivative (8). Reduction of the β- nitroalanine derivative (4a) gave the β- aminoalanine derivative (9), characterized by hydrolysis to 2,3- diaminopropionic acid hydrochloride.
Ultrasonic Velocities, Densities and Viscosities of (Prop-2-en-1-ol+Ethylbenzene or Isopropylbenzene) at 298.15 And 308.15 K
Authors: Rattan VK , Sethi BPS , Raju KSN
Published: September 2010

Isentropic compressibility, its excess value, excess molar volume, excess viscosity, and excess molar free energy for the activation of flow have been calculated from the experimental values of the speed of sound, density and viscosity at 298.15 and 308.15 K for mixtures of prop-2-en-1-ol with ethylbenzene or isopropylbenzene. The parameter d, of the Grunberg and Nissan expression, has also been calculated. The variation of the excess functions with composition indicates the absence of any specific interactions. In both the systems at 298.15 K, for alcohol mole fraction less than 0.66, the dissociation of the hydrogen-bonded alcohol agglomerates predominates over the association between unlike molecules. At the higher temperature the dissociation is predominant over the whole composition range.
A One- and Two-Dimensional 1H and 13C N.M.R. Study of Some Fernene Triterpenoids
Authors: Wilkins AL , Elix JA , Gonzalez AG , Perez C
Published: September 2010

A complete assignment of the 1H and 13C n.m.r. signals of the lichen triterpenoid 12α-acetoxyfern-9(11)-en-3 β-ol (lb) has been achieved by using one- and two-dimensional n.m.r. techniques. Evidence in support of one of two recently advanced assignments of the methyl group resonances of fern-9(11)-en-3-β-ol (1a) is presented.
Crystal Structure of Alloxan Monohydrate: A Redetermination
Authors: Harrowfield JM , Skelton BW , Soudi AA , White AH
Published: September 2010

The structure of the title compound, C4H4N2O5, has been redetermined by single-crystal X-ray diffraction methods at c. 295 K. Crystals are triclinic, P1, a 8.217(2), b 6.809(2), c 5.765(4) �, α 66.49(3),β 81.87(3), γ 74.35(2)�, Z= 2; the structure was refined by full-matrix least squares to a residual of 0.042 for 2190 independent 'observed' reflections, typical non-hydrogen interatomic distances being determined with estimated standard deviations of 0.001 �. Together with the recent precise redetermination of the structure of alloxan , these results allow comparison of the geometries of essentially planar polycarbonyl (-hydrate) arrays with those of long-chain arrays previously recorded.
A New Equilibrium Model for the Bazarov Urea Synthesis Process
Authors: Bagnell LJ , Hodges AM , Linton M , Mau AWH
Published: September 2010

A new equilibrium model for the high temperature and pressure Bazarov urea synthesis process is presented. By including the formation of ammonium hydroxide as an important equilibrium in the process the model can quantitatively predict the yield of urea under the following range of synthesis conditions: NH3/C02 ratios (L) greater than 2, when no excess water is added, in the temperature range 170-210�C. The model also predicts the observed maximum in urea yield with temperature for a given L> 2. New experimental data for L> 9 are presented that confirm the model's prediction that the yield of urea asymptotically approaches 100% at high L ratios. These data also reveal a pressure dependence for the urea yields which becomes more pronounced with increasing temperature and L ratio. In this region the agreement between theory and experiment is generally within 3% in the pressure range 30-50 MPa. Enthalpies of reaction for the formation of urea from ammonium carbamate and for the formation of ammonium hydroxide under urea synthesis conditions have been derived, and are 26 and -40 kJ mol-1 respectively, the former being in good agreement with a value estimated from literature data.
Pentakis(methoxycarbonyl)cyclopentadiene Chemistry. XIII. Some Metal Derivatives of 1-Methyl-2,3,4,5-tetrakis(methoxycarbonyl)cyclopentadiene. X-Ray Structure of Au[C5Me(Co2Me)4](PPh3)
Authors: Bruce MI , Humphrey PA , Williams ML , Skelton BW , White AH
Published: September 2010

Reactions of HC5Me(CO2Me)4 or TI[C5Me(CO2Me)4] with appropriate precursors have afforded the compounds ML2{C5Me(CO2Me)4}2 (M = Mn , L = H2O; M = Cu, L = MeOH ), Rh (ŋ4C8H12 )}ŋ5 -C5Me(CO2Me)4}, Rh {C5Me(CO2Me)4]2,RU(ŋ-C5H5){η5(C5Me(CO2Me)4}, Cu{C5Me(CO2Me)4}-(PPh3)2 and M{C5Me(COP2Me)4}(PPh3)(M=Ag or Au). There appear to be no significant differences between these compounds and analogous species derived from HC5(CO2Me)5, except for the expected spectroscopic changes. The molecular structure of Au{C2Me(CO2Me)4}(PPh3) closely resembles that of Au{C5(CO2- Me)5}(PPh3); the methyl group is on the ring carbon adjacent to that which most closely interacts with the Au(PPh3) group. Crystals are monoclinic, space group P21/c, with a 10.313(2), b 10-388(3), c 28.637(11)�, β 97.01(3)�, Z 4; 3571 data with I> 3σ) were refined to R 0.037, R′0.033.
X-Ray Crystal Structure of [Rh(OH2)6](ClO4)3.3H2O
Authors: Fallon GD , Spiccia L
Published: September 2010

The crystal structure of [Rh(OH2)6](ClO4)3.3H2O has been determined by single-crystal X-ray diffraction and found to be isomorphous with that of M(ClO4)2.6H2O (M= Fe, Zn, Mn, Co, Ni) and LiClO4.3H2O. Crystal: are hexagonal, space group P63mc with unit cell dimensions a 7.817(2) and c 5.208(1) �. The lattice consists of a uniform arrangement of H2O and ClO4- groups with the RhIII centre occupying 1/3 of the octahedral sites formed by the H2O groups. The RhIII is not situated at the centre of the octahedron. However, the two Rh-O distances [2.128(6) and 2.136(6) �] may be considered identical, i.e. within the errors.
Organic Curing Agents for Polysulfide Sealants. III. A Mechanistic Interpretation of the Thermal Degradation of Nitrile Oxide-Cured Polysulfide Sealants
Authors: Ennis BC , Hanhela PJ , Paul DB
Published: September 2010

Sealants obtained by cure of polysulfide liquid polymers with aryl bis ( nitrile oxides) possess the thiohydroximic acid ester structural feature. Unexpectedly these materials were found to exhibit poor thermal stability: when heated at 60° they soften within days and liquefy in 3 weeks. Products obtained with excess nitrile oxide degraded faster than those produced with equimolar amounts of reagents. Interpretations considered included (A) dissociation of the thiohydroximic acid group, (B) reaction between nitrile oxide and a reactive centre in the polysulfide structure, and (c) addition of nitrile oxide to the side chain. It was shown that neither of the first two possibilities was applicable. Moreover, spectroscopic studies demonstrated that, after an initial rapid addition between nitrile oxide and thiol , a second slower reaction occurred which consumed additional nitrile oxide. Although aldehyde oximes and a- chloro oximes do not participate in such processes unless catalysts are present, thiohydroximic acid derivatives were shown to react with nitrile oxides at ambient temperature to form 1,2,4-oxadiazole 4-oxides and alkyl thiol . For the case of a polysulfide sealant the equivalent rupture of a C-S bond to form the thiol involves cleavage of the polymer backbone. Continuation of the process would lead to degradation of the sealant. These observations were supported by thermal analysis studies on the polysulfide sealants and model polymers.
Conversion of Abietic Acid Into Analogs of Ambergris Odorants
Authors: Cambie RC , Rutledge PS , Ryan GR , Strange GA , Woodgate PD
Published: September 2010

The conversion of methyl abietate (16) into (42) and (43), analogues of the known amber odorants (1) and (2), is reported.
Synthesis of Substituted (+)-Bicuculline Derivatives Through Chloromethylation
Authors: Allan RD , Apostopoulos C
Published: September 2010

Treatment of the phthalide isoquinoline alkaloid (+)- bicuculline with paraformaldehyde and hydrochloric acid leads to the chloromethyl derivative (4) which can be further substituted with ammonia or piperazine . In reactions to study methods of linking bicuculline to macromolecules or to photolabile groups, the amino product (7a) has been further functionalized by the formation of amide linkages with succinic anhydride and 4-aminobenzoic acid.
Cage Precursor Ligands: A Sexidentate Triamine Trioxime and Its Complexes With Cobalt(III)
Authors: Engelhardt LM , Harrowfield JM , Mcniven SJ , Skelton BW , White AH
Published: September 2010

The ligand ' tamox ' (CH3C{CH2NHC(CH3)2C(CH3)=NOH}3) has been synthesized from 1,1,1-tris ( aminomethyl )ethane and 2-chloro-2-methyl-3-nitrosobutane. The ligand forms a deep yellow cobalt(III) complex which crystallizes readily from acidic solution as a monohydrated chloride diperchlorate salt. An X-ray structure determination on the monoclinic crystals, space group P21/c, a 10.254(4), b 22.30(1), c 15.375(8) Ǻ, β 117.16(4)°, Z 4, was refined to conventional R= 0.048 for 4573 'observed' reflections. The ligand is sexidentate with distinctly different bonding interactions of the two types of nitrogen-donor atoms ({Co- Namine } 1.97, {Co- Noxime } 1.92 Ǻ). The chloride anion interacts strongly with the complex cation through symmetrical hydrogen bonding to all three oxime hydroxyl protons. From neutral solution, the complex can be crystallized as an approximately trihydrated dichloride, the ligand having lost one proton ( pKa ≈ 3, I= 1.0, at 298 K). An X-ray structure determination for these crystals, monoclinic, P21/c, a 12.565(3), b 14.686(12), c 18.524(16) Ǻ, β 123.88(2)°, Z 4, R 0.054 for 3900 'observed' reflections, shows that neither chloride anion has any special mode of association with the cation. Attempts to 'cap' the [Co( tamox )]3+ complex by reactions with aqueous borate and phenyl boronate were unsuccessful. There is apparently a minor side reaction in the formation of the cobalt complex, a reaction which leads to the hydrolysis of one of the oxime groups of the ligand and the generation of a trans- dichlorocobalt (III) complex of this hydrolysed ligand in a quadridentate form. The nature of this green material has been established by an X-ray structure determination of its perchlorate salt, monoclinic, P21/c, a 14.38(2), b 18.20(1), c 14.71(2)Ǻ, β 118.80(7)°, Z 4, R 0.070 for 2120 'observed' reflections.
Micellar Catalysis of Organic Reactions. XXX. A Study of the Mechanism of Hydrolysis of Oxazepam and 2'-Methyldiazepam in the Presence of Micelles and in Water
Authors: Broxton TJ , Wright S
Published: September 2010

Acidic hydrolysis of oxazepam in water involved initial azomethine cleavage at low acid concentrations (0.1-0.2 M) with initial amide hydrolysis occurring concurrently at higher acid concentrations (0.3-0.6 M). In the
presence of micelles of sodium dodecyl sufate the percentage of initial amide cleavage increased. For the basic hydrolysis of oxazepam in water the rate was dependent on [ NaOH ] indicating at least some initial amide hydrolysis. At higher base concentrations the rate became independent of [ NaOH ], because of the ionization of the NH group of oxazepam, producing an unreactive nitranion. In the presence of cetyltrimethylammonium bromide, the rate of basic hydrolysis was slower than in water, due to the increased amount of ionization in the presence of micelles. Acidic hydrolysis of 2′-methyldiazepam in water was independent of [ HCl ] in the range 0.1-0.3 M, indicating initial azomethine hydrolysis. The rate was slower than for diazepam itself, indicating the existence of steric hindrance by the 2′-methyl group to water attack at C5. In basic solution, a biphasic reation was observed. The rate of the first phase was dependent on [ NaOH ], indicating the presence of initial amide hydrolysis for 2′-methyldiazepam, cf. initial azomethine hydrolysis for diazepam. At high base concentrations, a greater than first-order dependence on base concentration was observed. This was attributed to the formation of dianionic intermediates, as previously reported for the hydrolysis of similar anilides at high base concentrations.
A Simple Synthesis of Amphimedine
Authors: Prager RH , Tsopelas C , Heisler T
Published: September 2010

The marine alkaloid amphimedine has been synthesized by a short sequence of reactions commencing from the known indenopyridinedione (2). Reaction with 4-pyridyllithium, followed by hydrazoic acid treatment, gave 5-(4-pyridyl)-3,6-phenanthrolin-4(3H)-one (12) which was converted into the chlorophenanthroline. The methyl-substituted fluorosulfonate salt of this compound was specifically oxidized by alkaline ferricyanide. Conversion of the pyridone into the nitrile gave the precursor which was cyclized to amphimedine by polyphosphoric acid.
Synthesis of Casein-Related Peptides and Phosphopeptides. XI. Synthesis of Ac-Gly-Ser(P)-Gly-NHMe and Ac-Glu-Ser(P)-Leu-NHMe Through Phenyl Phosphate Protection
Authors: Perich JW , Johns RB
Published: September 2010

The two O-phosphoseryl -containing peptides, Ac-Gly -Ser(P)-Gly-NHMe and Ac-Glu -Ser(P)- Leu-NHMe were prepared by the use of Boc-Ser(PO3Ph2)-OH in the Boc mode of peptide synthesis for the preparation of the protected Ser(PO3Ph2) peptides, followed by cleavage of the phenyl phosphate groups by platinum-mediated hydrogenolysis.