Reaction of β-alkoxyvinyl halomethyl ketones with cyanoacetohydrazide

Abstract

The synthesis of thirteen 1-cyanoacetyl-5-hydroxy-5-halomethyl-1H-4,5- dihydropyrazoles from the reaction of 4-alkoxy-3-alken-2-ones [R 3C(O)C(R2)=C(R1)(OR), where R3 = CF3, CCl3, CHCl2, CO2Et; R 2 = H, Me; R1 = H, Me, Et, Pr, Pentyl, c-Hexyl, Ph, and R = Me, Et] with cyanoacetohydrazide is reported. In order to show the versatility of using the 1-cyanoacetyl-substituted pyrazoles as important building blocks in organic synthesis, some attempts to obtain pyrazole derivatives also are described. ©2008 Sociedade Brasileira de Química.