Piperidones are a class of chemical compounds sharing the piperidone skeleton. A classic named reaction for the synthesis of piperidones is the Petrenko-Kritschenko Piperidone synthesis which involves combining a alkyl-1, 3-acetonedicarboxylate with benzaldehyde and an amine. This multicomponent reaction reaction related to the Hantzsch pyridine synthesis.Some 4-piperidones give very good antimicrobial activity. So, here are some substituents of 4-piperidone to check whether I t give same activity or not.