PIPERAZINONES USEFUL AS INHIBITORS OF PLATELET AGGREGATION

摘要

The present invention provides compounds and medicines effective for prophylaxis and therapy of various diseases by controlling or inhibiting cell-adhesion. Especially, the compounds of this invention perform platelet aggregation action without remarkable elongation of hemorrhagic period and can be used as a safe and long-acting antithrombotic drug as compared with known substances showing the same activity. Compounds of this invention are piperazinones of formula (I) wherein A<1> and A<2> independently are a proton-accepting group or a group convertible into the proton-accepting group; D is a spacer having a 2 to 6 atomic chain optionally bonded through a hetero-atom and/or a 5- or 6-membered ring (provided that the 5- or 6-membered ring is, depending on its bonding position, counted as 2- or 3-atomic chains); R<1> is hydrogen atom or a hydrocarbon group; R<2> is hydrogen atom or a residual group formed by removing -CH(NH2)COOH from an alpha-amino acid, or R<1> and R<2> may be combined to form a 5- or 6-membered ring; P is a spacer having a 1- to 10- atomic chain optionally bonded through a hetero-atom and/or a 5- or 6-membered ring (provided that the 5- or 6-membered ring is, depending on its bonding position, counted as 2- or 3-atomic chains); Y is an optionally esterified or amidated carboxyl group; and n is a number ranging 0 to 8, and salts thereof.