Microwave-Assisted Regiospecific Synthesis of 2-Trifluoromethyl-7- Trihalomethylated Pyrazolo[1,5-a]Pyrimidines

Abstract

The reaction of 5-trifluoromethyl-3-aminopyrazole with 1,1,1-trihalo-4-alkoxy-3-alken-2-ones CX3C (O)C(R2) = C(R1)OR, [where R2 = H, Me; R1 = H, alkyl, aryl, OEt and R = alkyl] both in the presence of environmentally benign microwave induced techniques and by the conventional method furnished eleven regiospecific halomethylated pyrazolo[1,5-a]pyrimidines. 1H- and 13C-NMR spectroscopy established that the 7-hydroxy-5-ethoxy-pyrazolo[1,5-a]-6,7-dihydropyrimidine intermediate was also formed. Keywords: green chemistry, microwave irradiation, enones, pyrazoles, Pyrimidines