SYNTHESIS AND UNIMOLECULAR RADICAL-NUCLEO PHILIC SUBSTITUTION-REACTIONS IN THE 3-NITROIMIDAZO[1,2-A]PYRIMIDINE SERIES

A new heterocyclic reductive alkylating agent, 2-chloromerhyl-3-nitroi midazo[1,2-a] pyrimidine, is synthesized for the first time and shown to react under phase-tranfer catalysis conditions with 2-nitropropane anion to give good yield of the C-alkylated derivative. Elimination of nitrous acid allows to obtain a new class of imidazo[1,2-a]pyrimidine derivatives bearing a trisubstituted ethylenic bond in the 2 position . The S(RN)1 mechanism of C-alkylation is confirmed by classical inhib ition experiments by dioxygen, p-dinitrobenzene or TEMPO.