A one-pot three-step synthesis for the preparation of 3,4-dihydroquinazolines is developed. This method involves a reductive amination of o-azidebenzaldehydes with amines followed by N-acylation using azoyl chloride and Staudinger/ intramolecular aza-Wittig sequence in the presence of P(Bu-n)₃. Aromatic amines, benzylamines, and aliphatic chain amines could complete this multi-step reaction. The yield of butylamine, however, was slightly lower. Satisfactory yields can be obtained when aromatic acyl chloride containing electron-donating groups on the benzene ring was used. However, aromatic acyl chloride with electron withdrawing chlorine atoms and acryloyl chloride failed to give the corresponding products.

Key words: 3,4-dihydroquinazoline, synthesis, reductive amination, intramolecular aza-Wittig reaction