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Synthesis of trifluoromethyltriazoles from trifluoroacetohydrazonoyl bromide
Author(s) -
Tanaka Kiyoshi,
Honda Osamu,
Minoguchi Kazumi,
Mitsuhashi Keiryo
Publication year - 1987
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.5570240532
Subject(s) - chemistry , isothiocyanate , carbodiimide , bromide , pyridine , medicinal chemistry , isocyanate , trifluoromethyl , double bond , phenyl isothiocyanate , reactivity (psychology) , alkyl , intramolecular force , organic chemistry , medicine , alternative medicine , pathology , polyurethane
N ‐Phenyltrifluoroacetohydrazonoyl bromide ( 1 ) reacted with potassium isothiocyanate and isocyanate to give 5‐imino‐4‐phenyl‐2‐trifluoromethyl‐δ 2 ‐1,3,4‐thiadiazoline and 1‐phenyl‐3‐trifluoromethyl‐δ 2 ‐1,2,4‐triazolin‐5‐one, respectively. On treatment with several types of cumulative double bonds such as alkyl isothiocyanate, isocyanate, and carbodiimide, 1 afforded regioselectively the corresponding trifluoromethylthiadiazoline, ‐oxadiazoline, and ‐triazoline, respectively. These cycloadducts were assumed to form through the stepwise path involving the addition of 1 toward the cumulative double bond followed by the intramolecular cyclization. Concerning cyanamides, the corresponding triazoles were obtained and the reactions with pyridines afforded the triazolopyridinium bromides. The reactivity of the latter was found to depend on the substituents on the pyridine nucleus.