Four component synthesis of highly functionalized pyrano[2,3-<i>c</i>]pyrazoles from benzyl halides

2017-10-23T14:49:41Z (GMT) by Mallappa Beerappa Kalegowda Shivashankar
<p><i>N</i>-methylmorpholine <i>N</i>-oxide and silver oxide (Ag<sub>2</sub>O) oxidized four component reaction for the preparation of pyranopyrazole with different substituted pattern have been developed which provides rapid access to a library of compounds in good to excellent yields by using benzyl halide, malanonitrile/ethyl cyanoacetate, diethylacetylenedicarboxylate/ethyl acetoacetate and hydrazine hydrate as reactants. This transformation involves the breaking of one C‒O bond and formation of 2 C–C, 2 C–N, and a C‒O bond leading to the formation of a five and six membered ring in one pot operation.</p>