One‐Pot Synthesis of Highly Substituted 1H‐Pyrazole‐5‐carboxylates from 4‐Aryl‐2,4‐diketoesters and Arylhydrazines |
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Authors: | Jiao‐Jiao Zhai Chun‐Hui Gu Ying Guo Dao‐Hua Liao Dun‐Ru Zhu Ya‐Fei Ji |
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Affiliation: | 1. School of Pharmacy, East China University of Science and Technology, Shanghai, China;2. State Key Laboratory of Materials‐Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing, China |
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Abstract: | A one‐pot synthesis of highly substituted 1H‐pyrazole‐5‐carboxylates 1 has been developed starting from easily available 4‐aryl‐2,4‐diketoesters 2 and arylhydrazine hydrochlorides 3 . More active 2‐carbonyl group of 2 was blocked with methoxyamine hydrochloride to give 2‐methoxy imine intermediates, which were then subjected to condensation cyclization with 3 in situ to provide the desired products 1 . In addition, the geometrical configuration of 1aa was unambiguously confirmed by single crystal X‐ray crystallography. |
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Keywords: | One‐pot synthesis 1H‐Pyrazole‐5‐carboxylates 4‐Aryl‐2,4‐diketoesters Arylhydrazines |
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