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Efficient Synthesis of Dihydropyrazoles by Halocyclization of β,γ‐Unsaturated Hydrazones
Author(s) -
Hu XiaoQiang,
Chen JiaRong,
Wei Qiang,
Liu FengLei,
Deng QiaoHui,
Xiao WenJing
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402021
Subject(s) - chemistry , hydrazone , reaction conditions , combinatorial chemistry , organic chemistry , n bromosuccinimide , catalysis , halogenation
An efficient halocyclization of β,γ‐unsaturated hydrazones with N ‐bromosuccinimide was developed without the addition of any additives under mild reaction conditions to provide facile access to biologically important 4,5‐dihydropyrazoles. Under the optimized conditions, a variety of highly substituted 4,5‐dihydropyrazole derivatives were obtained in generally good yields. Moreover, this reaction can be further applied to the synthesis of pyrazoles in a one‐pot fashion.