A One-pot Approach to Ethyl 1,4,5-Triaryl-1<i>H</i>-pyrazole-3-carboxylates via an Improved Claisen Condensation-Knorr Reaction Sequence
作者:Jiaojiao Zhai、Chunhui Gu、Jianan Jiang、Shunli Zhang、Daohua Liao、Lei Wang、Dunru Zhu、Yafei Ji
DOI:10.1002/cjoc.201300776
日期:2013.12
one‐pot approach to ethyl 1,4,5‐triaryl‐1H‐pyrazole‐3‐carboxylates has been developed in moderate to high yields. The tert‐BuOLi‐mediated Claisen condensation of 1,2‐diarylethanones and ethyl oxalyl chloride efficiently provided the enolized lithium salts of ethyl 2,4‐dioxo‐3,4‐diarylbutanoates, which in situ reacted with arylhydrazine hydrochlorides via a hydrochloric acid‐promoted Knorr reaction to produce
Reaction of thiosemicarbazide with n-cyanoguanidine: synthesis of 3,5-diamino-1-thiocarbamoyl-and 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles
作者:V. M. Chernyshev、A. E. Kosov、E. S. Gladkov、S. V. Shishkina、V. A. Taranushich、S. M. Desenko、O. V. Shishkin
DOI:10.1007/s11172-006-0257-4
日期:2006.2
The reaction of thiosemicarbazide with N-cyanoguanidine in an acidic medium afforded 3,5-diamino-1-thiocarbamoyl-1,2,4-triazole, whose condensation with α-halo ketones gave 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles 7a–d. The latter were also prepared by the independent synthesis from 2-hydrazinothiazoles and N-cyanoguanidine. Acylation of compounds 7a,d under mild conditions and their condensation