The unprecedented synthesis of novel spiro-1,2,4-triazolidinones

Glycine nitrate mediated an environmentally benign, simple method which is reported for synthesis of novel spiro-1,2,4-triazolidinones from isatin and semicarbazide/thiosemicarbazide in water with excellent yields. Unexpected formation of novel spiro-1,2,4-triazolidinones instead of 1,2,4-triazino derivatives is observed. Moreover, the method is applicable for a variety of isatins. Rapid eco-friendly reactions with high yields, easy work-up procedure as well as isolation of product, excellent catalyst recyclability, high atom economy, and novelty are the auxiliary advantages of the protocol.