Greener synthesis of spirooxindole in deep eutectic solvent

A simple and efficient synthesis of spirooxindole derivatives by one-pot, three-component reaction of isatins, malononitrile and different nucleophiles under catalyst-free condition in deep eutectic solvent is reported. A series of biological importance, spirooxindole derivatives were synthesized via a multicomponent reaction of isatin, or acenaphthoquinone, and malononitrile or cyanoacetic ester with 1,3-dicarbonyl compounds, naphtol and 4-hydroxycumarin in biodegradable choline chloride based deep eutectic solvent in good yields (50-95%). This green procedure has the advantages of higher yields, shorter reaction times, environmental friendliness, and easy work-up.(c) 2014 Elsevier B.V. All rights reserved.