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Abstract
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A simple and elegant synthesis of some novel bis?spiro pyranopyrazoles has been achieved via the condensation reaction between bis?isatins, malononitrile, hydrazine hydrate and ??ketoester derivatives in the presence of a catalytic amount of 1, 4?diazabicyclo [2.2.2] octane (DABCO) in ethanol at reflux conditions. The significant features of the present method are structure diversity, product complexity, procedure and work?up simplicity, environmentally friendly, good to excellent yields and catalyst recyclability.
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