A One-pot Approach to Ethyl 1,4,5-Triaryl-1H-pyrazole-3-carboxylates via an Improved Claisen Condensation-Knorr Reaction Sequence

Authors

  • Jiaojiao Zhai,

    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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  • Chunhui Gu,

    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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  • Jianan Jiang,

    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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  • Shunli Zhang,

    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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  • Daohua Liao,

    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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  • Lei Wang,

    1. State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China
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  • Dunru Zhu,

    Corresponding author
    1. State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China
    • Dunru Zhu, State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China

      Yafei Ji, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China, Tel./Fax: 0086-021-64253314

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  • Yafei Ji

    Corresponding author
    1. School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
    • Dunru Zhu, State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu 210009, China

      Yafei Ji, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China, Tel./Fax: 0086-021-64253314

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Abstract

A 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 the exquisite triarylpyrazole-3-carboxylates. The procedure promises a convenient access to this highly crowded framework for drug discovery.

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