N-Acyl-polypeptides and processes for the production thereof

N-Acyl-polypeptides comprising the basic sequence ##STR1## wherein "Acyl" is the acyl residue of an organic or inorganic acid; A is H or alkyl; >N--CH(Z)--CO-- and E are the residues of natural .alpha.-amino acids or corresponding (D)-amino acids; C is --Trp-- or --(D)Trp--; F is a terminal grouping; and Y.sub.1 and Y.sub.2 are each H or together are a direct bond; as well as their salt forms and complexes.

The present invention relates to novel N-acyl-polypeptides, processes for 
their production, pharmaceutical compositions comprising said 
N-acyl-polypeptides and their use as pharmaceutically active agents. 
More particularly the present invention relates to N-acyl-polypeptides of 
formula I, 
##STR2## 
wherein "Acyl" is the acyl residue of an organic or inorganic acid, 
A is hydrogen or C.sub.1-3 alkyl, 
&gt;N--CH(Z)--CO-- is 
(a) an (L)- or (D)-phenylalanine residue optionally ring-substituted by 
halogen, NO.sub.2, NH.sub.2, OH, C.sub.1-3 alkyl and/or C.sub.1-3 alkoxy, 
or 
(b) the residue of a natural .alpha.-amino acid other than defined under 
(a) above, or of a corresponding (D)-amino acid, 
whereby Z in &gt;N--CH(Z)--CO-- represents the remainder of said residue (a) 
or (b), 
B is --Phe-- optionally ring-substituted by halogen, NO.sub.2, NH.sub.2, 
OH, C.sub.1-3 alkyl and/or C.sub.1-3 alkoxy, 
C is --Trp-- or (D)-Trp- optionally .alpha.-N-methylated and optionally 
benzene-ring-substituted by halogen, NO.sub.2, NH.sub.2, OH, C.sub.1-3 
alkyl and/or C.sub.1-3 alkoxy, 
D is --Lys-- optionally .alpha.-N-methylated and optionally 
.epsilon.--N--C.sub.1-3 alkylated, 
E is the residue of a natural .alpha.-amino acid or of a corresponding 
(D)-amino acid, said residue being optionally .alpha.-N-methylated, 
F is a group of formula --COOR.sub.1, --CH.sub.2 OR.sub.2, 
##STR3## 
or 
##STR4## 
wherein R.sub.1 is hydrogen or C.sub.1-3 alkyl, 
R.sub.2 is hydrogen or the residue of a physiologically acceptable, 
physiologically hydrolysable ester, 
R.sub.3 is hydrogen, C.sub.1-3 alkyl, phenyl or C.sub.7-10 phenylalkyl, 
R.sub.4 is hydrogen, C.sub.1-3 alkyl or, when R.sub.3 is hydrogen or 
methyl, also a group of formula --CH(R.sub.5)--X, 
R.sub.5 is hydrogen, --(CH.sub.2).sub.2 --OH or --(CH.sub.2).sub.3 --OH, or 
represents the substituent attaching to the .alpha.-carbon atom of a 
natural .alpha.-amino acid and 
X is a group of formula --COOR.sub.1, --CH.sub.2 OR.sub.2 or 
##STR5## 
wherein R.sub.1 and R.sub.2 have the meanings given above, 
R.sub.6 is hydrogen or C.sub.1-3 alkyl and 
R.sub.7 is hydrogen, C.sub.1-3 alkyl, phenyl or C.sub.7-10 phenylalkyl, 
the group --CH(R.sub.5)--X having the (D)- or (L)-configuration, and 
Y.sub.1 and Y.sub.2 are each hydrogen or together represent a direct bond, 
whereby the residues in the 2- and 7-position each independently have the 
(L)- or (D)-configuration, and with the proviso that: 
(i) (L)- and/or (D)-cysteine residues are present at the 2- and 7-positions 
only, and 
(ii) "Acyl" may not represent a residue &gt;N--CH(Z)--CO-- as defined above, 
in which the .alpha.-amino group is unsubstituted or in mono- or 
di-C.sub.1-12 alkyl substituted, 
as well as the salt forms and complexes thereof. 
Throughout the present specification and claims by "halogen" is meant 
fluorine, chlorine and bromine. In accordance with conventional practice, 
amino acid residues referred to by abbreviation, e.g. --Phe--, --Cys-- 
etc., are to be understood as having the (L)-configuration unless 
otherwise indicated. 
Acyl residues as "Acyl" include, in particular, the acyl residues of 
organic carboxylic acids, sulfonic acids, sulfaminic acids and carbonic 
acids and their derivatives. Suitable acyl residues are, e.g. the groups: 
1. R.sup.I CO-- wherein R.sup.I is an aliphatic, cycloaliphatic, aromatic 
or heterocyclic group, especially C.sub.1-20 alkyl, C.sub.3-20 alkenyl, 
C.sub.3-20 alkinyl, phenyl, naphthyl or C.sub.7-10 (phenylalkyl); 
2. R.sup.II SO.sub.2 -- wherein R.sup.II is C.sub.1-10 alkyl, phenyl or 
C.sub.7-10 (phenylalkyl); 
3. R.sup.III O--CO-- wherein R.sup.III is C.sub.1-10 alkyl or C.sub.7-10 
(phenylalkyl); and 
##STR6## 
wherein R.sup.IV is hydrogen, C.sub.1-10 alkyl, phenyl or C.sub.7-10 
(phenylalkyl) and 
R.sup.V is hydrogen or C.sub.1-10 alkyl. 
Aliphatic groups as R.sup.I may be saturated or unsaturated, branched- or 
straight-chain. Similarly alkyl, alkenyl and alkinyl groups as well as the 
alkyl-moieties of phenylalkyl groups recited as R.sup.I through R.sup.V 
may all be branched- or straight-chain. All groups recited as R.sup.I 
through R.sup.V may optionally bear further substituents. Suitably groups 
recited as R.sup.I through R.sup.V are unsubstituted. 
In the N-acyl-polypeptides of formula I, the following significances or 
combinations thereof are preferred: 
5. "Acyl" is a group R.sup.I CO-- or R.sup.II SO.sub.2 -- as defined under 
1. and 2. above. Most preferably "Acyl" is a group R.sup.I CO--. 
5.1 When "Acyl" is a group R.sup.I CO--, R.sup.I is preferably C.sub.1-15 
alkyl, phenyl or C.sub.7-10 (phenylalkyl), more especially C.sub.1-15 
alkyl. 
5.2 When "Acyl" is a group R.sup.II SO.sub.2 --, R.sup.II is preferably 
C.sub.1-10 alkyl or phenyl optionally substituted by C.sub.1-3 alkyl, 
especially phenyl or mono- or di-C.sub.1-3 alkyl-substituted phenyl. Most 
preferably R.sup.II is C.sub.1-10 alkyl. 
6. A is hydrogen or methyl, especially hydrogen. 
7.1 When &gt;N--CH(Z)--CO-- has the meaning (a), it is preferably an (L)- or 
(D)-phenylalanine or (L)- or (D)-tyrosine residue (whereby Z is benzyl or 
p-OH-benzyl), most preferably a (D)-phenylalanine residue. 
7.2 When &gt;N--CH(Z)--CO-- has the meaning (b), the defined residue is 
preferably lipophilic. Preferred residues (b) are accordingly residues in 
which Z is alkyl having 3, preferably 4, or more carbon atoms, in 
particular one (L)- or (D)-leucine and (L)- or (D)-nor-leucine residues 
(in which case Z is iso- and n-butyl respectively). 
7.3 Most preferably &gt;N--CH(Z)--CO-- has the meaning (a). 
8. B is --Phe--. 
9. C is --(D)Trp--. 
10. D is --Lys-- or --MeLys--, especially --Lys--. 
11. E is the residue of a natural .alpha.-amino acid, especially --Thr--. 
12. F is a group of formula 
##STR7## 
especially a group of formula 
##STR8## 
(in which case R.sub.3 =H or CH.sub.3). In the latter case the moiety 
--CH(R.sub.5)--X preferably has the L-configuration. 
12.1 R.sub.3 is preferably hydrogen. 
12.2 As the substituent attaching to the .alpha.-carbon atom of a natural 
amino acid (i.e. of formula H.sub.2 N--CH(R.sub.5)--COOH), R.sub.5 is 
preferably --CH.sub.2 OH, --CH(CH.sub.3)--OH, isobutyl or benzyl, or 
R.sub.5 is --(CH.sub.2).sub.2 --OH or --(CH.sub.2).sub.3 OH. It is 
especially --CH.sub.2 OH or --CH(CH.sub.3)OH. 
12.3 X is preferably a group of formula 
##STR9## 
or --CH.sub.2 --OR.sub.2, especially of formula --CH.sub.2 OR.sub.2 and 
R.sub.2 is preferably hydrogen or has the meaning given under 13. below. 
Most preferably it is hydrogen. 
13. As the residue of a physiologically acceptable, physiologically 
hydrolysable ester R.sub.2 is preferably HCO, C.sub.2-12 -alkylcarbonyl, 
C.sub.8-12 phenylalkylcarbonyl or benzoyl. 
14. Preferably the residues in the 2- and 7-positions have the 
(L)-configuration. 
15. Preferably Y.sub.1 and Y.sub.2 together represent a direct bond. 
A particularly interesting group of N-acyl-polypeptides of formula I are 
those wherein "Acyl" represents an acyl residue incorporating an aliphatic 
moiety (e.g. as R.sup.I, R.sup.II, R.sup.III or R.sup.IV of the groups 
defined under 1. to 4. above) having at least 7, preferably at least 8 
carbon atoms, compounds of this type (hereinafter referred to as 
"N-acyl-polypeptides of Type-T") being characterised by a more prolonged 
duration of activity when administered sub-cutaneously. Preferred 
N-acyl-polypeptides of Type-T are those wherein "Acyl" is a group R.sup.I 
CO-- or R.sup.II SO.sub.2 --, especially a group R.sup.I CO--, wherein 
R.sup.I is C.sub.7-15 alkyl, preferably C.sub.7-10 alkyl, especially 
C.sub.8-15 alkyl, preferably C.sub.8-10 alkyl, and R.sup.II is C.sub.7-10 
alkyl, especially C.sub.8-10 alkyl. Especially preferred are 
N-acyl-polypeptides of Type-T, wherein the remaining residues in formula I 
have the significances specified under (6.) through (15.) above. 
The N-acyl-polypeptides of the invention may exist in salt form or in the 
form of complexes thereof. Acid addition salts may be formed with e.g. 
organic acids, polymeric acids and inorganic acids. Such acid addition 
salt forms include e.g. the hydrochlorides and acetates. By complexes are 
to be understood compounds of known type, formed from compounds of formula 
I on addition of inorganic substances, e.g. inorganic salts or hydroxides 
such as Ca- and Zn-salts, and/or on addition of polymeric organic 
substances. 
The present invention also provides a process for the production of the 
compounds according to the invention. These compounds may be produced by 
methods known in the art of peptide chemistry or by obvious chemical 
equivalents thereof, for example by a process comprising: 
(a) removing the protecting group or groups from a protected 
N-acyl-polypeptide having the sequence indicated in formula I, 
(b) linking together by an amide bond two peptide units, each of which 
contains at least one amino acid or amino alcohol residue in protected or 
unprotected form, the peptide units being such that a protected or 
unprotected N-acyl-polypeptide having the sequence indicated in formula I 
is obtained and, if necessary, carrying out process step (a); 
(c) converting the group F of a protected or unprotected N-acyl-polypeptide 
having the sequence indicated in formula I, into another group F, and, if 
necessary carrying out process step (a); 
(d) oxidising an N-acyl-polypeptide of formula I wherein Y.sub.1 and 
Y.sub.2 are each hydrogen to provide an N-acyl-polypeptide of formula I, 
wherein Y.sub.1 and V.sub.2 together are a direct bond, 
and recovering the N-acyl-polypeptide thus obtained in free or salt form or 
as a complex thereof. 
The above process may for example be carried out analogously to the 
processes described in the accompanying examples. Insofar as the 
production of the starting materials is not particularly described, the 
compounds are known or may be produced and purified in accordance with 
methods known in the art. In the following examples [.alpha.].sub.D.sup.20 
values are uncorrected. The following abbreviations are employed: 
AcOH=acetic acid 
AcOEt=ethyl acetate 
BOC=tert.-butoxycarbonyl 
BTFA=boron-tris-trifluoroacetate 
DCCI=dicyclohexylcarbodiimide 
DMF=N,N-dimethylformamide 
HOBT=N-hydroxybenzotriazole 
Leu-ol=the leucinol residue 
##STR10## 
MBzl=p-methoxybenzyl Me=methyl 
MeOH=methanol 
NEt.sub.3 =triethylamine 
ONP=4-Nitrophenoxy 
Phe(pNO.sub.2)=p-NO.sub.2 -Phenylalanine 
TFA=trifluoroacetic acid 
THF=tetrahydrofuran 
Thr-ol=the threoninol residue 
##STR11## 
Z=benzyloxycarbonyl