Nano SiO2 Catalyzed Chemo-Selective Synthesis of N′-Benzylidene-2-cyano-2-(10-oxophenanthren-9(10H)-ylidene) or (2-Oxoindolin-3-ylidene)acetohydrazide Derivatives

Two new categories of Michael acceptors: N '-benzylidene-2-cyano-2-oxophenanthren acetohydrazides and N '-benzylidene-2-cyano-2-oxoindolin acetohydrazides, have been successfully synthesized via a one-pot three-component reaction using cyanoacetohydrazide, aromatic aldehydes and 9,10-phenanthroquinone or isatin in a mixture of water and ethanol in the presence of nano sized SiO2 as a heterogeneous catalyst at reflux conditions. The new efficient approach involves two chemo-selective sequences of hydrazone formation and Knoevenagel condensation. The benefits of this process include availability of starting compounds, simplicity of operation and work-up procedure, good to excellent yields, the use of green solvents and high chemo-selectivity of products.