Scheme 2From: Utility of 2-thioxo-pyrido[2,3-d]pyrimidinone in synthesis of pyridopyrimido[2,1-b][1,3,5]-thiadiazinones and pyridopyrimido[2,1-b][1,3]thiazinones as antimicrobial agentsSynthesis of pyridopyrimidothiazinone derivatives (12a–c) and (14)Back to article page