Borolysine peptidomimetics

A compound of formula I ##STR18## wherein:

• W is hydrogen or an N-protecting group
• Y is a sequence of n amino acids such that the n+1 amino acid peptide Y-Lys or Y-Arg has an affinity for the active site of a trypsin-like protease;
• where n is an integer of from 1 to 10 and in which at least one amino acid is an unnatural amino acid having a hydrophobic side chain;
• Q.sub.1 and Q.sub.2 are the same or different and are selected from --OH, --COR.sub.1, --CONR.sub.1 R.sub.2, --NR.sub.1 R.sub.2 or --OR.sub.3 or --OR.sub.3 or Q.sub.1 and Q.sub.2 taken together form a diol residue;
• R.sub.1, R.sub.2 and R.sub.3 which may be the same or different, are C.sub.1-10 alkyl, C.sub.6-10 aryl, C.sub.6-10 aralkyl or phenyl substituted by up to three groups selected from C.sub.1-4 alkyl, halogen and C.sub.1-4 alkoxy;
• R.sub.4 is hydrogen or C.sub.1-10 alkyl
• R.sub.5 is a group --A--X;
• wherein
• A is --(CH.sub.2).sub.z -- in which z is 2,3,4 or 5;
• --CH(CH.sub.3)--(CH.sub.2).sub.2 --;
• --CH.sub.2 --CH(CH.sub.3)--CH.sub.2 ;
• --(CH.sub.2).sub.2 --CH(CH.sub.3)--;
• --(CH.sub.2).sub.2 --C(CH.sub.3).sub.2 --;
• --CH(CH.sub.3)--(CH.sub.2).sub.3 --;
• --CH.sub.2 --CH(CH.sub.3)--(CH.sub.2).sub.2 --;
• --CH.sub.2 --CH.sub.2 --CH(CH.sub.3)--CH.sub.2 --;
• (CH.sub.2).sub.3 --;CH(CH.sub.3)--;
• --(CH.sub.2).sub.3 --C(CH.sub.3).sub.2 :
• C.sub.6-10 aryl C.sub.6-10 aralkyl and
• X is --NH.sub.2, --NH--C(NH)--NH.sub.2, --S--C(NH)--NH.sub.2 --, --N.sub.3, C.sub.1-4 alkoxy, C.sub.1-4 alkylthio or --Si(CH.sub.3).sub.3 or
• R.sub.4 and R.sub.5 together form a trimethylene group and the asymmetric carbon atom marked * may have the D- or L-configuration or represent any mixture of these.