A One-pot Approach to Ethyl 1,4,5-Triaryl-lH-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 

机构地区：[1]School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China [2]State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China

出　　处：《Chinese Journal of Chemistry》2013年第12期1526-1538,共13页中国化学（英文版）

基　　金：The authors are grateful to the National Natural Science Foundation of China (Nos.21176074 and 21171093) for financial support

摘　　要：A one-pot approach to ethyl 1,4,5-triaryl-lH-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 the exquisite triarylpyrazole-3- carboxylates. The procedure promises a convenient access to this highly crowded framework for drug discovery.A one-pot approach to ethyl 1,4,5-triaryl-lH-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 the exquisite triarylpyrazole-3- carboxylates. The procedure promises a convenient access to this highly crowded framework for drug discovery.

关 键 词：one-pot approach 2 4-dioxo-3 4-diarylbutanoates Claisen condensation Knorr reaction triarylpyrazole-3-carboxylates 

分 类 号：TQ246.31[化学工程—有机化工] O631.5[理学—高分子化学]