New one-pot and regioselective method for the synthesis of 3-trifluoromethyl-1H-1-phenylpyrazoles

Pyrazoles derivatives has been extensively explored by our research group contemplating their biological activities. 1 Efficient approaches to introduce a CF3 group at the C-3 position of pyrazole ring in a regioselective manner has been getting attention, mostly because these compounds often show pharmacological activities such as the antiinflammatory Celecoxib ® and the anticoagulant Razaxaban ® and the anticoagulant Razaxaban ® . So, we report an efficient and regioselective insertion of a CF3 group into pyrazole rings from the reaction of 4-alkoxy-1,1,1-trifluoroalk-3-en-2-ones [CF3C(O)CH =CR 1 (OR) where R = Me or Et, R 1 = H, Me, Ph, 2-Furyl and R 1 -R 2 = -C4H8-] (1a-e) and 1-phenylsemicarbazide (2) in order to obtain 3-trifluoromethyl-1-phenylpyrazoles (3a-e) as the main isomer.