Reaction of 3-aminopyrrole with chloropyrimidines to give pyrroloaminopyrimidines

Reaction of 3-aminopyrrole with chloropyrimidines occured only at the 3-amino group. The activating group(s) (Cl, NO₂ or CF₃), their relative positions (C4/C6, C2, or C5), and the effect of added base (DIPEA) or acetic acid on the course of the reaction, was studied. When chloro groups were present on both C4/C6 and C2, the only or major product was from the displacement of the C4/C6 chloro group. Only in the reaction of 2,4,6-trichloropyrimidine was substitution at C2 competitive with reaction at C6. Both chloro groups of 2,4-dichloro-3-nitropyrimidine were displaced to give a novel compound with three-linked heterocyclic rings. Reactions of less reactive chloropyrimidines appeared to be favored by acid catalysis.