One-pot and regioselective synthesis of polysubstituted 3,4-dihydroquinazolines and 4,5-dihydro-3H-1,4-benzodiazepin-3-ones by sequential Ugi/Staudinger/aza-Wittig reaction

An efficient one-pot and regioselective synthesis of 3,4-dihydroquinazolines and 4,5-dihydro-3H-1,4-benzodiazepin-3-ones by Ugi/Staudinger/aza-Wittig sequence has been developed. The Ugi reactions of 2-azidobenzylamines, aldehydes, acids (or alpha-keto acids) and isocyanides produced the azide intermediates, which were then treated with tributylphosphine or triphenylphosphine to give poly-substituted 3,4-dihydroquinazolines or 4,5-dihydro-3H-1,4-benzodiazepin-3-ones in moderate to good yields by tandem Standinger/aza-Wittig reactions. (C) 2019 Elsevier Ltd. All rights reserved.