EP0096517A3 — Aryl pyrazinones

USPTO Abstract

Pyrazinone derivatives of the formula (I): or a pharmaceutically acceptable salt thereof, wherein R¹, R² and R³ are independently hydrogen or C₁₋₄ alkyl, and R⁴ 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 R⁴ is a group -CO-(NR⁵) n R⁶ wherein n is zero or one, R⁶ is hydrogen, optionally substituted C₁₋₆ alkyl, optionally substituted phenyl, or optionally substituted pyridyl, and R⁵ is hydrogen, C₁₋₆ alkyl or R⁵ and R⁶ 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.