Ultrasound irradiation promotes the synthesis of new 1,2,4-triazolo [1,5-a]pyrimidine

Ultrasonic irradiation was used in the synthesis of a series of novel 1,2,4-triazolo[1,5-a]pyrimidines. The products were synthetized from the cyclocondensation reaction of 1,1,1-trifluoro-4-metoxy-3-alken-2one [CF3C(O)CH=C(R)OMe, where R = Ph, 4-F-C6H4, 4-Br-C6H4, 4-I-C6H4, 4-CH3(-)C(6)H(4), 4-CH3O-C6H4, Thien-2-yl, Biphen-4-yll or p-enaminones [RC(0)CH=CHNMe2, where R = Ph, 4-F-C6H4, 4-Br-C6H4, 4-l-C6H4, 4-CH3-C6H4, 4-CH3O-C6H4, 4-NO2-C6H4, Thien-2-yl, Biphen-4-yl, Naphth-2-yl, Pyrrol-2-yl, CO3] with 5-amino-1,2,4-triazole in acetic acid at 99 degrees C with 5-17 min of ultrasound irradiation. This methodology has shown several advantages, such as shorter reaction times, mild conditions, high regioselectivity, and excellent yields, when compared with conventional thermal heating (oil bath). (C) 2013 Elsevier B.V. All rights reserved.