New efficient synthesis of trisubstituted imidazolidine-2-thiones and thiazoles via vinyliminophosphoranes
作者:Hai Xie、Jian-Chao Liu、Lei Wu、Ming-Wu Ding
DOI:10.1016/j.tet.2012.07.002
日期:2012.9
Isothiocyanate 6, obtained from vinyliminophosphorane 4 with CS2, reacted with various aliphatic primary amines to afford directly the 1,4,5-trisubstituted imidazolidine-2-thiones 5. However, the reaction of isothiocyanate 6 with aliphatic secondary amines provided 2,4,5-trisubstituted thiazoles 10 in good yields.
A novel and efficient reaction of vinyl azides with Bestmann-Ohira reagent for the regioselectivesynthesis of phosphonylpyrazoles is presented. Reaction proceeds through 1, 3 dipolar cycloaddition with an excellent yield in short period of time under mild reaction conditions. Moreover, no column purification is involved for the isolation of products.