Microwave-assisted synthesis of novel 5-trichloromethyl-4,5-dihydro-1H-1- pyrazole methyl esters under solvent free conditions

Abstract

Twelve novel 5-trichloromethyl-4,5-dihydro-1H-1-pyrazole ethyl esters have been synthesized in good yields (70-98%) by using environmentally benign microwave induced techniques. The compounds were synthesized from the cyclocondensation of 1,1,1-trichloro-4-alkoxy-3-alken-2-ones [CCl 3C(O)C(R2)=C(R1)OR, where R, R2 = H, alkyl; R1 = H, alkyl and aryl] with hydrazine methyl carboxylate. The advantages obtained by the using of microwave irradiation under solvent-free conditions, rather than a conventional method, were demonstrated. © 2006 Sociedade Brasileira de Química.