A One‐pot Approach to Ethyl 1, 4, 5‐Triaryl‐1H‐pyrazole‐3‐carboxylates via an Improved Claisen Condensation‐Knorr Reaction Sequence. Issue 12 (11th December 2013)

• Record Type: Journal Article
• Authors: Zhai, Jiaojiao; Gu, Chunhui; Jiang, Jianan; Zhang, Shunli; Liao, Daohua; Wang, Lei; Zhu, Dunru; Ji, Yafei
• Is Part Of: Chinese journal of chemistry. Volume 31:Issue 12(2013:Dec.)
• Page Start: 1526
• Page End: 1538
• Publication Date: 2013-12-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cjoc.201300776
• Languages: English
• ISSNs: 1001-604X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A one‐pot approach to ethyl 1, 4, 5‐triaryl‐1<italic>H</italic>‐pyrazole‐3‐carboxylates has been developed in moderate to high yields. The <italic>tert</italic>‐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.</p> </abstract>