Access to quinazolines from 2-nitrobenzaldehyde and arylamines

Abstract

A synthesis of N-(2-nitrobenzyl)acetanilide (5) and (11) from 2- nitrobenzaldehyde and aromatic amines is reported. The reaction of amides (5) and (11) with iron in acetic acid-ethanol-water provided the corresponding 3- phenyl-π-1,2,3,4-tetrahydroquinazolines (7) and (12). Reductive cyclization of 1-acetyl-2-(2-nitrophenyl)-benzimidazol (16) to benzimidazo[1,2- c]quinazoline (19) and benzimidazol (20) is described.