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Photochemistry of trifluromethyl substituted 1‐methylpyrazoles
Author(s) -
Pavlik James W.,
Na Ayudhaya Theppawut Israsena,
Pandit Chennagiri R.,
Tantaya Supawan
Publication year - 2004
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.5570410110
Subject(s) - chemistry , pyrazole , ring (chemistry) , yield (engineering) , transposition (logic) , medicinal chemistry , stereochemistry , organic chemistry , linguistics , materials science , philosophy , metallurgy
Trifluromethyl substitution on the pyrazole ring was found to enhance photoreactivity via the P 4 pathway which involves interchange of the N2‐C3 ring atoms. Thus, 1‐methyl‐3‐(trifluromethyl)pyrazole (1) and 1‐methyl‐5‐(trifluromethyl)pyrazole (3) transposed with a P 4 /P 6 or P 4 /P 6 +P 7 ratio of 2.1:1. 1‐methyl‐4‐(trifluromethyl)pyrazole (2) transposed regiospecifically by the P 4 transposition pathway. Compounds 2 and 3 were also observed to undergo photocleavage to yield enaminonitrile and enaminoisocyanide products.