1.
"Reported, but still unknown." A closer look into 3,4-bis- and 3,4,5-tris(trifluoromethyl)pyrazoles.
J Org Chem
; 77(1): 47-56, 2012 Jan 06.
Artigo
em Inglês
| MEDLINE
| ID: mdl-22171748
RESUMO
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 pK(a) values and fluorescence measurements.