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Reactions of a 4‐(trifluoromethyl)thiazole dianion
Author(s) -
South Michael S.,
Van Sant Karey A.
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.5570280431
Subject(s) - chemistry , thiazole , trifluoromethyl , electrophile , aldehyde , chloride , fluoride , medicinal chemistry , ketone , organic chemistry , allylic rearrangement , catalysis , inorganic chemistry , alkyl
Treatment of 2‐trifluoroacetamido‐4‐(trifluoromethyl)thiazole with two equivalents of n ‐butyllithium at ‐78° produced the thiazole dianion 5 in situ , which reacted preferentially at the 5‐position with a variety of electrophiles. These electrophiles include: an aldehyde, ketone, chloroformate, acid chloride, phosphorus oxychloride, silicon chloride, and disulfide. Dianion 5 also combined with dibromodifluoromethane at ‐98° to give the corresponding 5‐(bromodifluoromethyl)thiazole 7 , which is an unusual reaction for an aromatic or heteroaromatic system. Compound 7 was converted to a 4,5‐ bis ‐(trifluoromethyl)thiazole 8 using tetrabutylammonium fluoride.