Synthesis and discovery of novel piperidone-grafted mono- and bis-spirooxindole-hexahydropyrrolizines as potent cholinesterase inhibitors

1,3-Dipolar cycloadditions of 1-acryloyl-3,5-bisbenzylidenepiperidin-4-ones with isatin and l-proline in 1:1:1 and 1:2:2 molar ratios afforded, respectively mono- and bisspiropyrrolizines and were assayed for their AChE and BuChE activities.