Studies on 1,3-benzoxazines. I. Synthesis of primary 2-amino-pyridines via the reaction of imidoyl chlorides of 1,3-benzoxazines with pyridine N-oxides.

Abstract

A new synthetic method for primary 2-aminopyridine derivatives is described. Treatment of the imidoyl chlorides of 1, 3-benzoxazines (1a-i) with pyridine N-oxides resulted in the introduction of an oxazine moiety into the α-position of the pyridine ring through rearrangement of the initially formed reaction adduct. Acid hydrolysis of the rearrangement products afforded 2-aminopyridine derivatives in excellent yields. When methoxypyridine N-oxides were used, products of a different type (10 and 14) were obtained.