Antithrombotic peptides and pseudopeptides

A compound of the formula ##STR30## wherein:

• A is ##STR31## B and D are independently --CH.sub.2 --NH--, --CH.sub.2 --S--, --CH.sub.2 --O--, ##STR32## B may also be 5-tetrazol-1-yl or --CR.sub.7 .dbd.CR.sub.8 --;
• Z is --OR.sub.a, a D- or L-isomer of an .alpha.-amino acid bonded at the .alpha.-nitrogen, a dipeptide bonded at the N-terminal .alpha.-amino acid, or --NR.sub.a R.sub.x, where R.sub.x is H or ##STR33## where V is ##STR34## --(CH.sub.2).sub.p --, --CH.dbd.CH--, --CH.sub.2 NH--, --CH.sub.2 --O--, or --CH.sub.2 --S--;
• R.sub.e and R.sub.f are independently H, alkyl, cycloalkyl, cycloalkylmethyl, or --(CH.sub.2).sub.s --R.sub.z where R.sub.z is --COOR.sub.n, --OR.sub.n, --SR.sub.n, --NR.sub.n, R.sub.o, ##STR35## R.sub.1-10, and R.sub.n are independently H, alkyl, cycloalkyl, cycloalkylmethyl, aryl, substituted aryl, aralkyl or substituted aralkyl;
• R.sub.a, R.sub.g, R.sub.n', and R.sub.o are independently H, alkyl, cycloalkyl, cycloalkylmethyl;
• R.sub.t is --H, --COOH, --COOR.sub.k, carbamoyl, or ##STR36## where R.sub.k and R.sub.m are independently H, alkyl, cycloalkyl, cycloalkylmethyl;
• Y.sub.1 is H, amino or ##STR37## where R.sub.p is H, alkyl, cycloalkyl, cycloalkylmethyl, aryl, substituted aryl, aralkyl or substituted aralkyl;
• x, x', x", x'" and x"" are independently 0 or 1;
• m.sub.1 and m.sub.2 are independently 0 to 9;
• h.sub.1, h.sub.2, and k are independently 0 or 1;
• n is 1 to 3;
• q is 1 to 5;
• and p and s are independently 0 to 6;
• provided that when ##STR38## is arginyl-glycyl-aspartyl, then Z is other than a naturally occurring amino acid or a dipeptide composed of two naturally occurring amino acids;
• and provided that Z is other than serine or a pharmaceutically acceptable salt thereof.