A Facile Construction of 6-(Arylmethyl)imidazo[1,2-a]pyrimidin-7-ylamines from Allylamines Derived from Baylis-Hillman Adducts

A facile and convenient synthesis of substituted imidazo[1,2‐a]pyrimidin‐7‐ylamines from the allylamine derivatives afforded by the Baylis–Hillman acetates of substituted benzaldehydes and heterocyclic aldehydes by treatment with cyanamide is described. Interestingly, the allylamines afforded by heterocyclic aldehydes, which undergo fast Baylis–Hillman reaction, were discovered to undergo a one‐pot reaction, whereas allylamines derived from all other aldehydes reacted by a two‐step procedure.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) A convenient route to the imidazo[1,2‐a]pyrimidine core by reaction of cyanamide with appropriately substituted allylamines afforded by Baylis–Hillman chemistry followed by an intramolecular cyclization is presented. The protocol was discovered tobe a one‐pot reaction for the allylamines generated from the heterocyclic aldehydes undergoing fast Baylis–Hillman reaction, whereas it was a two‐step procedure for all other aldehydes.