Facile synthesis of ninhydrin and isatin based hydrazones in water using PEG-OSO3H as a highly efficient and homogeneous polymeric acid-surfactant combined catalyst

The synthesis of a series of biologically important ninhydrin and isatin based hydrazones has been carried out by refluxing easily synthesized novel N′-(chloro-aryl-methylene)-tert-butylcarbazates with ninhydrin and isatins in the presence of PEG-OSO3H as catalyst in water medium. The dual characteristic of PEG-OSO3H as a Brønsted acid as well as a phase-transfer catalyst is successfully exploited in this synthesis. Reduced reaction time, operational simplicity, excellent yields of the products with high purity, and more importantly, easy recoverability, and reusability of the homogeneous polymeric catalyst make the reaction an attractive, economic, and sustainable green synthetic methodology.