Selective and Solvent‐Free Synthesis of Isoxazole‐Containing Spiro‐Thiazolidinones Using TiO2‐SO3H as Solid Catalyst. Issue 33 (30th August 2019)

• Record Type: Journal Article
• Authors: Singh, Ruby; Singh, Aakash; Bhardwaj, Diksha
• Is Part Of: ChemistrySelect. Volume 4:Issue 33(2019)
• Page Start: 9600
• Page End: 9607
• Publication Date: 2019-08-30
• Subjects: α-Mercaptocarboxylic acids -- Multicomponent Reaction -- Solvent-free -- Spiro-thiazolidinones -- n-TSA -- Regioselectivity; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201901942
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: A solvent‐free nano‐titania‐supported sulfonic acid [nano‐TiO2 ‐SO3 H (n‐TSA)] catalyzed approach has been developed for the synthesis of pharmaceutically interesting new hybrids of isoxazolyl‐spiro‐thiazolidinones. The key feature of present investigated three component reaction of cyclic ketones (isatin, ninhydrin and acenaphthenequinone), 3‐amino‐5‐methyl‐isoxazole and α‐mercaptocarboxylic acids involves the synthesis of a five member ring system instead of the anticipated seven member ring system & also exploits the possibility of other likely isomers, regio and diastereoselectively. The selectivity of synthesized spiro‐thiazolidinone systems was established, based on the spectroscopic outcome and single crystal X‐ray analyses of representative compounds. Further, the use of a solid catalyst, n‐TSA under solvent‐free conditions was observed to be the best choice of reaction conditions, as it not only afforded the product in higher yields in less reaction time but in an environmentally friendly manner as well. Abstract : In this work, diverse pharmaceutically interesting new hybrid isoxazolyl‐spiro‐thiazolidinones have been synthesized selectively on the surface of SO3 H immobilized titania (TiO2 ‐SO3 H) under solvent‐free conditions in higher yields.