Mechanisms for the acetylation of aminopyridines

Abstract

Rates of acetylation of aminopyridines and some ring methyl-substituted derivatives, with acetic anhydride in acetone at 36°, are reported. The results indicate that rate-determining acetylation is directly at the amino nitrogen for all 2- and 3-aminopyridines studied. Reaction through a ring N-acetyl intermediate occurs for 4-aminopyridine but the presence of a 2-methyl substituent blocks this pathway.