Acid-catalyzed allenylation of pyrazolones with propargyl alcohols
Wande Zhang1, Shiqiang Wei1, Jingping Qu1
1State Key Laboratory of Fine Chemicals, Department of Pharmaceutical Sciences, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, People's Republic of China. bmwang@dlut.edu.cn.
Abstract:
A TsOH-catalyzed allenylation of pyrazolones with propargylic alcohols has been developed. The established reaction system is well tolerated by a wide scope of pyrazolones and propargylic alcohols. The process has the salient features of operational simplicity, facile scale-up and high yield. In particular, the integration of the pharmaceutical-related pyrazolone skeleton and the allenyl group into a single molecule not only enriches the structural diversity of the pyrazolone scaffold, but potentially also contributes to a broader spectrum of biological activity. Furthermore, it is easy to synthesize 3aa in gram-scale with the yield and efficiency basically maintained, making the practical application of this process more prominent.
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