Urea/thiourea catalyzed, solvent-free synthesis of 5-arylidenethiazolidine-2,4-diones and 5-arylidene-2-thioxothiazolidin-4-ones
作者:Sakshi Shah、Baldev Singh
DOI:10.1016/j.bmcl.2012.07.049
日期:2012.9
An efficient and organo-catalyzed method has been developed for the synthesis of 5-arylidenethiazolidine-2,4-diones and 5-arylidene-2-thioxothiazolidin-4-ones via Knoevenagel condensation of arylaldehydes 1 and 2,4-thiazolidinedione 2a/2-thioxothiazolidin-4-one 2b under mild conditions. Urea-adduct 4 and azomethine 5 also afford arylidene-products 3 by reacting with 2a-b via addition-elimination reaction. This protocol has the features of use of inexpensive, ecofriendly readily available, effective catalyst system viz. urea/thiourea, avoidance of volatile solvents, excellent yield and simple work-up procedure. (C) 2012 Elsevier Ltd. All rights reserved.
Reductive alkylation of thioureas: a highly practical synthesis of unsymmetrical N,N′-disubstituted thioureas
作者:Lech Ciszewski、Daquiang Xu、Oljan Repič、Thomas J. Blacklock
DOI:10.1016/j.tetlet.2004.08.182
日期:2004.10
A highly practical synthesis of unsymmetrical N,N′-disubstitutedthioureas by the reductive alkylation of N-monosubstituted thioureas with aldehydes is described. N-Monosubstituted thioureas can in turn be synthesized by the reductive amination of thiourea with an appropriate aldehyde. This reductive alkylation methodology was also extended to carbamates.