Sarita Khandelwal, Anshu Rajawat, Yogesh Kumar Tailor, Anju Kulhari and Mahendra Kumar Pages 69 - 74 ( 6 )
Background: The development of novel synthetic methods for the synthesis of structurally diverse drug-like molecules with environmentally friendly solvents and catalysts is significant in the development of drug discovery research. The synthesis of fused heterocycles has attracted considerable interest because the fusion of biologically active heterocyclic systems has proved to be an attractive and useful approach for designing potential drugs with a wide spectrum of pharmacological activities. Multicomponent reactions with their highly convergent characteristics offer an opportunity to provide druglike small molecules with structural diversity and molecular complexity. The present synthetic protocol involves the tandem reaction of hydrazine hydrate, 3-aminocrotononitrile, isatins and carbonyl compound using GAAS as environmentally benign and sustainable catalytic solvent.
Method: spirooxindoles spiroannulated with indenopyrazolopyridine, chromenopyrazolopyridine, and pyranopyrazolopyridine have been synthesized by multicomponent reaction of hydrazine hydrate, 3- aminocrotononitrile, cyclic 1,3-diketones, and substituted isatines in the presence of gluconic acid aqueous solution (GAAS, 50 wt%) as catalytic solvent.
Results: we have presented diversity oriented efficient and environmentally benign synthetic protocol for the synthesis of structurally diverse spiroannulated pyrazolo[3,4-b]pyridines using gluconic acid aqueous solution (GAAS, 50%, wt%) as an inexpensive and eco-friendly bio-based catalytic solvent.
Conclusion: The operational simplicity with mild reaction conditions, shorter reaction times, excellent product yields and environmentally benign reaction conditions with reusability of catalytic solvent render the present protocol both attractive and economically viable for the synthesis of medicinally privileged spiroannulated heterocycles. We believe that the present work will contribute considerably not only to the chemical research, but also to the medicinal research.
Chromenopyrazolopyridine, diversity oriented synthesis, environmentally benign synthetic protocol, GAAS, indenopyrazolopyridine, pyranopyrazolopyridine, spiroheterocycles.
Department of Chemistry, University of Rajasthan, Jaipur, 302004