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Preparation of 1,3‐Disubstituted‐5‐ cyano‐4,5‐dihydropyrazoles via 1,3‐Dipolar Cycloaddition of Nitrile Imine with Acrylonitrile
Author(s) -
Song LiPing,
Zhu ShiZheng,
Huang JiLing
Publication year - 2002
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20020201121
Subject(s) - chemistry , nitrile , acrylonitrile , imine , benzene , aldehyde , cycloaddition , 1,3 dipolar cycloaddition , organic chemistry , acetonitrile , combinatorial chemistry , catalysis , polymer , copolymer
Oxidation of aldehyde 4‐chloro‐2, 3,5, 6‐tetrafluorophenylhydrazones (1) with [bis(acetoxy)iodo] benzene leads to the formation of nitrile imines (2) which can react in situ with acrylonitrile to produce l‐(4‐chloro‐2,3,5,6‐tetrafluorophenyl)‐3‐substituted‐5‐cyano‐4, 5‐dihydropyrazoles (3) in moderate to good yields. The structures of new compounds were fully confirmed by their spectral data and elemental analyses. A plausible reaction mechanism for the generation of nitrile imine is proposed.