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Synthesis of some trifluoromethyl substituted 1‐methylpyrazoles
Author(s) -
Pavlik James W.,
Ayudhya Theppawut Israse,
Tantaya Supawan
Publication year - 2003
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.5570400619
Subject(s) - trifluoromethyl , chemistry , methylhydrazine , regioselectivity , polar , medicinal chemistry , ethanol , organic chemistry , stereochemistry , catalysis , alkyl , physics , astronomy , phenylhydrazine
The major products from the reaction of β‐alkoxyvinyl trifluoromethyl ketones 1a‐c with methylhydrazine ( 2 ) in absolute ethanol are the 3‐(trifluoromethyl)‐substituted‐1‐methylpyrazoles 3a‐3c with lesser amounts of the 5‐(trifluoromethyl)‐substituted products 4a‐4c and 5a‐5c. Carrying out the reaction in non‐polar, aprotic solvents can further enhance the regioselectivity favoring the 3‐ (trifluoromethyl) ‐substituted isomers.