Synthesis 2015; 47(13): 1877-1886
DOI: 10.1055/s-0034-1379906
paper
© Georg Thieme Verlag Stuttgart · New York

Catalyst-Free and Oxidant-Free Synthesis of 1,3,5-Trisubstituted Pyrazoles by Michael-Type Addition of Hydrazone sp2 Nitrogen Atoms to Enones

Chunyin Zhu*
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. of China   Email: zhucycn@gmail.com
,
Benwei Bi
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. of China   Email: zhucycn@gmail.com
,
Dewei Yao
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. of China   Email: zhucycn@gmail.com
,
Qiu-Yun Chen
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. of China   Email: zhucycn@gmail.com
,
Zhi-Bin Luo
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. of China   Email: zhucycn@gmail.com
› Author Affiliations
Further Information

Publication History

Received: 28 December 2014

Accepted after revision: 05 March 2015

Publication Date:
31 March 2015 (online)


Abstract

A new single-step approach to 1,3,5-trisubstituted pyrazoles from hydrazones and α,β-unsaturated keto esters has been developed. This catalyst- and oxidant-free transformation involves a Michael-type addition of the hydrazone sp2 nitrogen to the enone and a redox isomerization. The procedure has a wide substrate scope and shows good compatibility with both α-ester- and α-keto-substituted hydrazones.

Supporting Information