Nano-ZnO catalyzed green and efficient one-pot four-component synthesis of pyranopyrazoles

An efficient zinc oxide nanoparticle catalyzed one-pot,four-component synthesis of 6-amino-3-methyl-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles from aromatic aldehyde,malononitrile,ethyl acetoacetate,and hydrazine hydrate in aqueous medium is described. since water was employed as the reaction medium,it serves as a green route for the synthesis of pyrano[2,3-c]pyrazoles. the advantages associated with the present protocol include nonchromatographic purification technique,use of recyclable heterogeneous nano-zno catalyst in aqueous medium,and short reaction time. it combines successfully the synergistic effect of green chemistry with nanocatalysis. © 2013 sunil u. tekale et al.