.gamma.-turn peptidomimetics as fibrinogen antagonists

A compound of the formula:

• ##STR22## wherein:
• Q is NR' or O;
• D is ##STR23## E and F are (H,H), O or S;
• G is N or C;
• V is H, R', SR', A-B-O or A-B-NR';
• A is H, R', (CH.sub.2).sub.n Ar, R.sub.1 CO, R.sub.1 OCO, R.sub.1 OCH(R.sub.1')CO, R.sub.1 NHCH(R.sub.1')CO, R.sub.1 SCH(R.sub.1')CO, R.sub.1 SO.sub.2 or R.sub.1 SO;
• R.sub.1 and R.sub.1' are H, C.sub.1-5 alkyl, C.sub.3-7 cycloalkyl, aryl or aryl substituted by one or two C.sub.1-5 alkyl, trifluoromethyl, hydroxy, C.sub.1-5 alkoxy or halogen groups;
• R.sup.2 is N(R').sub.2, NR'C(.dbd.O)NHR', C(.dbd.NR')NHR' or NR'C(.dbd.NR')NHR';
• B is absent, Arg, HArg, (Me.sub.2)Arg, (Et.sub.2)Arg, Ala, Gly, His, Abu or an .alpha.-R' substituted derivative thereof, or Pro;
• X is R", CHRCH.sub.2 -Y-Z or CHRCO-Y-Z;
• Y is absent or a D- or L- amino acid chosen from Tyr, (Alk)Tyr, Phe, (4'W)Phe, HPhe, Phg, Trp, His, Ser, (Alk)Ser, Thr, (Alk)Thr, Cys, (Alk)Cys, Pen, (Alk)Pen, Ala, Val, Nva, Met, Leu, Ile, Nle and Nal;
• Z is R" or OR", NR'R" or R";
• R is H, C.sub.1-6 alkyl, (CH.sub.2).sub.n Het, (CH.sub.2).sub.n CONHR', (CH.sub.2).sub.n NR'R', (CH.sub.2).sub.n NC.dbd.N-NR', (CH.sub.2).sub.n OR' or (CH.sub.2).sub.n SR' or (CH.sub.2).sub.n Ar;
• R' is H, C.sub.1-4 alkyl or (CH.sub.2).sub.n Ar;
• R" is H, C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, amino, Ar, (CHR').sub.n (CH.sub.2).sub.n -Ar, C.sub.3-7 cycloalkyl-Ar, Het, (CH.sub.2).sub.n Het or C.sub.3-7 cycloalkyl-Het;
• Ar is phenyl or naphthyl optionally substituted by one or two C.sub.1-5 alkyl, C.sub.1-5 alkoxy, C.sub.1-5 alkylthio, CO.sub.2 R', CON(R').sub.2, hydroxy, halogen, trifluoromethyl, amino or nitro groups.
• Het is pyridyl, indolyl, imidazolyl or thienyl substituted by one or two C.sub.1-4 alkyl, CO.sub.2 R', CON(R').sub.2, OR' or SR';
• - - is a single or double bond;
• m is 0 to 2;
• n is 0 to 3;
• p is 1 to 3;
• q is 1 to 4;
• and
• pharmaceutically acceptable salts thereof.