Methyl 3-(triphenylphosphoranylideneamino)pyrazine-2-carboxylate: synthesis, crystal structure and use in pteridin-4(3H)ones synthesis

Abstract

The title iminophosphorane 6 has been prepared from methyl 3-aminopyrazine-2-carboxylate 1 by a modified Kirsanov method using a triphenylphosphine–hexachloroethane–triethylamine system. The crystal structure of 6 illustrated an iminophosphorane function (NP bond). 2,3-Disubstituted pteridin-4(3H)-ones were obtained in a one-pot reaction of 6 with isocyanates, followed by heterocyclization on addition of alcohols or amines.