Resourceful synthesis of pyrazolo[1,5-a]pyrimidines under ultrasound irradiation

Pyrazolo[1,5-a]pyrimidines were synthesized via the ultrasonic sonochemical method using the cyclo-condensation reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3(C)(O)CH = C(R)(OMe) - where R = Me, Bu, i-Bu, Ph, 4-Me-C6H4, 4-F-C6H4, 4-CI-C6H4, 4-Br-C6H4, naphth-2-yl and biphen-4-yl] - with 3-amino-5-methyl-1H-pyrazole in the presence of EtOH for 5 min. This methodology has several advantages, for example, it is a simple procedure, it has an easy work-up, Mild conditions, short reaction times (5 min) and produces satisfactory yields (61-98%). (C) 2013 Elsevier B.V. All rights reserved.