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Synthesis of 5‐chloropyrazoles by chlorodediazoniation with sulfur dioxide
Author(s) -
Yamamoto Susumu,
Morimoto Katsushi,
Sato Toshiaki
Publication year - 1991
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570280613
Subject(s) - chemistry , sulfur dioxide , sulfur , catalysis , organic chemistry
A facile synthesis of 5 ‐chloropyrazoles 4a‐e from 5 ‐aminopyrazoles 2a‐e via diazotization followed by chlorodediazoniation is described. A new application of sulfur dioxide as a catalyst was demonstrated to be the best for the chlorodediazoniation of diazonium chlorides 3a‐e .