Ionic liquid promoted cyclocondensation reactions to the formation of isoxazoles, pyrazoles and pyrimidines

A simple one-pot procedure to obtain a series of five- and six-membered heterocycles, in three different ionic liquids ([BMIM][BF4], [BMIM][OH] and [HMIM][HSO4]) is described. The synthetic protocol involves the reaction between β-enamino ketone derived from 1,4-diacetylbenzene and hydroxylamine, hydrazines (R1NHNH2, where R1 = H, Ph, 4-O2N-Ph, 2,4-(O2N)2-Ph, C6F5, CO2Me, CONH2, CH2CH2OH, t-Bu) or amidines (R2C(NH)NH2, where R2 = NH2, Ph), furnishing bis-isoxazoles, bis-pyrazoles and bis-pyrimidines in good yields and short reaction times.