Green synthesis of pyranopyrazoles via biocatalytic one-pot Knoevenagel condensation–Michael-type addition–heterocyclization cascade in non-aqueous media

An efficient, green and facile route for the one-pot four-component synthesis of pyranopyrazole derivatives through the condensation of the aromatic aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate using baker’s yeast as biocatalyst is presented. The important aspects of the present methodology are the use of an environmentally friendly catalyst, high yield of products and mild reaction conditions, i.e. at neutral pH and...