One-pot NHC-assisted access to 2,3-dihydropyrimido[4,5-d]pyrimidin-4(1H)-ones

Abstract

An efficient N-heterocyclic carbene-assisted one-pot reaction for the synthesis of 2,3-dihydropyrimido[4,5-d]pyrimidin-4(1H)-ones from 2-(ethoxymethylene)malononitrile, guanidines (or amidines) and ketones (or aldehydes) has been developed. This highly efficient method includes a series of conversions such as Michael addition, cyclisation, isomerization, aromatization, then nucleophilic attack and Dimroth rearrangement. And it avoids complicated reagents and multiple steps.