A sequential multicomponent reaction toward the construction of a novel contiguous imino-thiazolidinone grafted dispiroheterocyclic scaffolds

Synthesis of structurally intriguing iminothiazolidinone tethered dispiropyrrolizidine/pyrrolothiazole hybrids have been achieved with complete regio- and diastereoselectivity in excellent yields <i>via</i> a one-pot three component 1,3-dipolar cycloaddition strategy employing alkyl-2-[(<i>Z</i>)-4-oxo-3-aryl/alkyl-2-(arylimino)thiazolidin-5-ylidene] acetates as dipolarophiles and azomethine ylide derived from two cyclic ketones (isatin and acenaphthaquinone) and cyclic amino acids (l-proline and l-thiaproline) using biodegradable deep eutectic solvent. During the entire transformation, three additional bonds are formed with generation of four stereogenic carbons in target molecule in a single step reaction. The synthesized compounds were structurally elucidated using NMR spectroscopic studies, and the regio-and stereoselectivity was determined through single crystal X-ray diffraction study.