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Schmidt B, Riemer M, Schilde U. Tandem Claisen Rearrangement/6-endoCyclization Approach to Allylated and Prenylated Chromones. European J Org Chem 2015. [DOI: 10.1002/ejoc.201501151] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Orrego-Hernández J, Cobo J, Portilla J. Chemoselective Synthesis of 5-Alkylamino-1H-pyrazole-4-carbaldehydes by Cesium- and Copper-Mediated Amination. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500505] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Zhong W, Chen X, Shen Y. A New Route to 5-Chloropyrazole-4-Carbaldehydes and their Behaviour in the Baylis–Hillman Reaction. JOURNAL OF CHEMICAL RESEARCH 2010. [DOI: 10.3184/030823410x12766918476516] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
5-Chloropyrazole-4-carbaldehydes were efficiently prepared via Vilsmeier reaction of 1H-pyrazol-5(4H)-ones with bis(trichloromethyl) carbonate-DMF instead of the traditional POCl3–DMF system. The Baylis–Hillman reaction of these aldehydes with activated alkenes promoted by various catalysts were investigated. It was found DMAP accelerated the reaction of methyl acrylate or acrylonitrile with the aldehydes, while in the case of but-3-en-2-one, a catalyst mixture of imidazole and L-proline (1:1) was efficient. Overall, the reactivities of the aldehydes were low.
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Affiliation(s)
- Weihui Zhong
- Key Laboratory of Pharmaceutical Engineering of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Xiao Chen
- Key Laboratory of Pharmaceutical Engineering of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Yanyan Shen
- Key Laboratory of Pharmaceutical Engineering of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China
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Yet L. Chapter 5.4: Five-Membered Ring Systems: With More than One N Atom. PROGRESS IN HETEROCYCLIC CHEMISTRY 2009. [DOI: 10.1016/s0959-6380(09)70035-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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