Enzyme inhibition

Claim 1

Polypeptide analogues of the formula: ##STR31## where X=H or an N-protecting group: F, Cl, Br, I, --CF 3 , --OH, --OR or --R (R=C 1 -C 6 alkyl) or R--O--CO-- where R=t-butyl, benzyl, 2,2,2-trichloroethyl or R 6 --SO 2 -- where R 6 =Ph, α-naphthyl β-naphthyl or one or more amino acyl residues either as such or in protected form bearing a group X above Y=absent, or glycine, or D- or L-phenylalanine or a lipophilic amino acid residue selected from the group consisting of Phg, Cha, α--Nal, β--Nal and p-iodophenylalanyl Z=L- or D-proline or a ring homologue selected from the group consisting of azetidine-2-carboxylic acid and piperidine-2-carboxylic acid or L- or D-valine or N-methyl-alanine or glycine or Y and Z are as: ##STR32## where the peptide bond --CO--NH-- between Y and Z has been reduced (and protected) to give --CH 2 --(X)--, X being a protective group as defined above A= ##STR33## (ii) R 2 =H, lower alkyl (C 1 -C 4 ) or 1-hydroxy-ethyl, (iii) R 3 =group X as defined above (iv) configuration at the asymmetric centres * is either R or S Arg or Pro and Arg may be absent, Pro or Pro substituted with hydroxy-proline and arg or Arg substituted with Z 1 , Tos or --NO 2 B=D or L-valine or D or L-proline or --NH--(CH 2 ) n --CO--, where n=0-5, or absent W=--OH --OR 4 where R 4 =lower alkyl (C 1 -C 5 ), --NH 2 --, --NHR 2 5 or --NH 5 where R 5 =lower alkyl (C 1 -C 5 ), cycloalkyl C 3 C 7 or cycloalkyl substituted with a group selected from carboxyl and alkyl (C 1 -C 5 ) group(s) B-W represents an aminoalcohol derivative of B as such or in protected form and where further in said compounds of formula I the two terminals are optionally linked by a peptide bond to form a cyclic structure.