PROCEDE POUR LA PREPARATION DES DERIVES DE PYPERAZIN-2-ONE

摘要

Pyrazinone derivatives of the formula (I): …… or a pharmaceutically acceptable salt thereof, wherein R<1>, R<2> and R<3> are independently hydrogen or C1-4 alkyl, and R<4> is hydrogen, a C1-6 alkoxycarbonyl group optionally substituted by amino, hydroxy, C1-4 alkoxy or carboxy (wherein the substituent is not on the carbon atom adjacent to the -CO-O moiety); or R<4> is a group -CO-(NR<5>)nR<6> wherein n is zero or one, R<6> is hydrogen, optionally substituted C1-6 alkyl, optionally substituted phenyl, or optionally substituted pyridyl, and R<5> is hydrogen, C1-6 alkyl or R<5> and R<6> form together with the nitrogen atom to which they are attached to piperidine, morpholino, piperazine or N-(C1-6)- alkyl-piperazine ring; are described. …Processes for their preparation are described, involving inter alia novel phenyl pyrazinone intermediates. Their use in pharmaceutical compositions is described, as is their use as inotropic agents.