New efficient synthesis of 1,2,4-trisubstituted imidazoles and imidazo[1,2-c]quinazolines by a tandem aza-Wittig/electrocyclic ring-closure process
作者:Yi-Bo Nie、Zhuan Duan、Ming-Wu Ding
DOI:10.1016/j.tet.2011.12.005
日期:2012.1
A series of 1,2,4-trisubstituted imidazoles 5 were synthesized efficiently by a tandem aza-Wittig/1,5-electrocyclic ring-closure reaction of vinyliminophosphoranes 3 with aldehydes. Reactions of 5s,t with triphenylphosphine produced iminophosphoranes 7. A tandem aza-Wittig reaction of iminophosphorane 7 with isocyanate generated imidazo[1,2-c]quinazolines 9 in high yields. (C) 2011 Elsevier Ltd. All rights reserved.