A facile access to novel spiroxindole fused pyrrolidine and thiazolo pyrrolidine benzimidazole derivatives via 1,3-dipolar cycloaddition reaction

A series of benzo[d]imidazol-2-yl)-V-methyl-2-oxo-4'-phenylspiro[indoline-3,2'-pyrrolidine] and benzo[d]imidazol-2-yl)-2-oxo-7'-phenyl-31,6',7',7ai-tetrahydro-1'H-spirotindoline-3,5'-pyrrolo[1,2-c]thiazole]carbonitrile were synthesized via 1,3-dipolar cycloaddition (1,3-DC) reaction. The azomethine ylides generated in situ from isatin/N-substituted isatin and secondary amino acids (sarcosine/S-proline) reacted with benzo-imidazol-2-y1-3-phenylacrylonitrile as a dipolarophile to give spiroxindole fused pyrrolidine and thiazolo pyrrolidine benzimidazole derivatives in good yields. The structure and stereochemistry of cycloadducts were confirmed by H-1 and C-13 NMR spectroscopy, mass spectrometry, and single crystal X-ray diffraction studies. (C) 2015 Elsevier Ltd. All rights reserved.