Studies on 1,3-benzoxazines. VI. Formation of quinazolines and 4H-3,1-benzoxazines by the reaction of 4-chloro-2H-1,3-benzoxazines with aminoacetophenone, aminobenzophenone and aminobenzyl alcohol derivatives.

A novel synthetic method for quinazoline and 4H-3, 1-benzoxazine derivatives is described. Reaction of 4-chloro-2H-1, 3-benzoxazine (1) with 2-aminoacetophenone (2a) gave rise to the quinazoline derivative (4a) in good yield, while treatment of aminobenzophenones (2b-e) with 1 afforded only substituted compounds (3b-e), which could be converted into quinazoline derivatives (4b-e) on heating in the presence of p-toluenesulfonic acid in toluene. Derivatives of 4H-3, 1-benzoxazines (10a-e) were prepared by the reaction of the aminobenzyl alcohols (7a-e) with 1. A possible mechanism for the formation of these reaction products is discussed.