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Novel perfluoroalkyl‐substituted pyrazoles. 1. Hydroxypyrazoles
Author(s) -
Gaede Bruce J.,
Mcdermott Lisa L.
Publication year - 1993
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.5570300110
Subject(s) - chemistry , steric effects , methylhydrazine , electronic effect , combinatorial chemistry , stereochemistry , medicinal chemistry , organic chemistry , computational chemistry , phenylhydrazine
Addition of methylhydrazine to a variety of haloalkyl‐substituted α,β‐unsaturated esters gives 1,5‐disubstituted 3‐hydroxypyrazoles, in contrast to the more common synthesis from β‐ketoesters, which gives 1,3‐disubstituted 5‐hydroxypyrazoles. This reaction is used to prepare several novel pyrazoles bearing haloalkyl substituents. Criteria for assignment of structures have been developed based on physical and spectroscopic properties of the isomers. The regiochemical preference in this addition is considered on the basis of steric, electronic, and mechanistic factors.