Heterocyclization of 1-aryl/alkyl-2-thiobiureas to 4-aryl/alkyl-3-substituted-Δ 2 -1,2,4-triazolin-5-ones
作者:M.M Suni、Vipin A Nair、C.P Joshua
DOI:10.1016/s0040-4020(01)00018-7
日期:2001.3
Synthesis of a range of 1,2,4-triazolin-5-ones has been carried out by thermally induced cyclization of 1-aryl/alkyl-2-alkyl isothiobiureas 4. The required isothiobiureas were generated in situ by the reaction of alkyl halides with 1-aryl/alkyl-2-thiobiureas 3 in acidic medium at reflux. The reaction proceeds after S-alkylation of the thiobiureas and is demonstrated by the isolation of the alkyl isothiobiurea intermediates and their subsequent acid catalyzed thermal cyclization. (C) 2001 Elsevier Science Ltd. All rights reserved.