A highly efficient and green method has been described for the synthesis of spiropyranopyrazole-oxindole in water. The reaction was carried out at ambient temperature and the products were obtained in excellent isolated yields. The structure of the product (4e) was confirmed by X-ray diffraction analysis.
An efficient mild one-pot synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole derivatives by a four-component reaction of hydrazine, a β-keto ester, isatin, and malononitrile catalysed by L-proline in water is reported.