| |
[摘要]：A study is presented for the synthesis of a series of 1-tert-butyl-3(5)-(trifluoromethyl)-1H-pyrazoles from the reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)CH=C(R1)(OR), where R = Et and R1 = H or R = Me and R1 = Me, Ph, 4-Me-C6H4, 4-MeO-C6H4, 4-F-C6H4, 4-Cl-C6H4, 4-Br-C6H4, 4-I-C6H4, fur-2-yl, thien-2-yl, or naphth-2-yl] with tert-butylhydrazine hydrochloride. When [BMIM][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and pyridine were used as the reaction media, we obtained a mixture of 1-tert-butyl-3(5)-trifluoromethylpyrazoles. The formation of 5-trifluoromethyl-1-tert-butyl-1H-pyrazoles with high regioselectivity occurred when the reaction was carried out with NaOH in EtOH. The formation of 1-tert-butyl-3-trifluoromethyl-1H-pyrazoles occurred, after hydrolysis of the 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones in H2O and H2SO4, followed by cyclization in [BMIM][BF4] and pyridine. |
|
