Synthesis of 4,6-diarylpyrimidin-2(1H)-one derivatives from benzyl halides and (1-bromoethyl)benzene under solvent-free conditions

A facile synthesis of a series of pyrimidinone derivatives from the reaction of benzyl halides, (1-bromoethyl)benzene and urea in the presence of pyridine N-oxide (PNO) under solvent-free conditions is described. This transformation presumeably occurs via oxidation/cross-aldol condensation/Michael addition/intra molecular cyclization, domino sequence, involving the formation of one C–C bond and two C–N bonds in a single step.

Pyridine N-oxide (PNO) has been demonstrated to be efficient and mild reagent for the one-pot synthesis of 4,6-diarylpyrimidin-2(1H)-ones (DAPMs) from a variety of benzyl halides and (1-bromoethyl)benzene instead of benzaldehydes and acetophenone respectively with short reaction times and excellent yields.