Heterocyclic derivatives as inhibitors of platelet aggregation.

Compounds of formula (I) and metabolically labile esters and amides thereof, and pharmaceutically acceptable salts thereof, wherein R {sup, 13}, M {SUP, 2}, X {SUP, 1}, Z {SUP, 1}, {Z SUP, 1A}, X {SUP, 2} AND {SUP, 1} REPRESENTING THE DATA SPEC. The compounds are useful as inhibitors of LINK FIBRINOGENES glycoproteins IIB / IIIA. ALSO NEW INTERMEDIATE ARE PRESENTED.