Synthesis of highly functionalised dispiropyrrolidine derivatives as novel acetylcholinesterase inhibitors

In the effort of finding novel acetyl cholinesterase (AChE) inhibitors to improve the efficacy of Alzheimer's disease (AD) treatment, series of substituted aryl-1′-methyldispiro[indan-2,2′ pyrrolidine-3′, 2"-indan]-1,3,1′-trione and substituted 7′-aryl-5′, 6′,7′,7a′-tetrahydrodispiro-[indane-2,5′-pyrrolo[1,2-c] [1,3]thiazole-6′,2"-indan]-1,3,1"-trione analogues were synthesized using [3+2]-cycloaddition reactions. These newly synthesized pyrrolidine compounds were assayed for their biological activity using Ellman's method. The structural elucidation of the compounds was performed by using 1^H-NMR, 13^C-NMR, ESI-MS spectra and elemental analyses. Eight out of twenty synthesized compounds showed more than 50% inhibition at concentration of 10 μM. Compound 2e, 2i and 3e were among the most active one, giving IC₅₀ value as 3.3 μM for 2e, 3.7 μM for 2i and 5.5 μM for 3e, respectively. Lineweaver-Burk plot indicated that 2i inhibits AChE in a competitive manner. Molecular modelling study was performed to disclose the binding interaction of these compounds with the active site of AChE.