“Reported, but Still Unknown.” A Closer Look into 3,4-Bis- and 3,4,5-Tris(trifluoromethyl)pyrazoles
journal contributionposted on 22.02.2016, 09:58 by Igor I. Gerus, Roman X. Mironetz, Ivan S. Kondratov, Andrei V. Bezdudny, Yurii V. Dmytriv, Oleg V. Shishkin, Viktoriia S. Starova, Olga A. Zaporozhets, Andrey A. Tolmachev, Pavel K. Mykhailiuk
Straightforward practical synthetic approaches to 3,4-bis- and 3,4,5-tris(trifluoromethyl)pyrazoles have been developed. The key step of the both syntheses is a transformation of the carboxylic group in a pyrazole core into the trifluoromethyl group by sulfur tetrafluoride. The elaborated synthetic protocols allow gram-scale preparation of the target products. The obtained compounds are comprehensively characterized by means of crystallographic analysis, determination of pKa values and fluorescence measurements.