Synthesis, characterization, crystal structure, and antituberculosis activity of some novel polysubstituted aminocarbothiol/thiohydantoin-pyrrolidine derivatives

A series of novel functionalized polysubstituted aminocarbothiol/thiohydantoin-pyrrolidine derivatives were prepared from amino acid esters and aldehyde via cascade aldimine-azomethine ylide-1,3-dipolar cycloaddition and condensation reaction with benzoyl isothiocyanates afforded the corresponding aminocarbothiol pyrrolidines in an atom economy manner, which were conveniently converted into functionalized trisubstituted bicyclic thiohydantoins fused to pyrrolidine ring by sequential cyclization reaction under mild reaction conditions in good yield. The characterization and structural determination were made by spectral and X-ray crystal structural analysis. The crystal structure of cis-methyl (5R,6S,7aR)-7a-benzyl-5-(2,4-dimethoxyphenyl)-1-oxo-3-thioxohexahydro-1H-pyrrolo[1,2-c]imidazole-6-carboxylate was determined as monoclinic, space group P-1 type using single X-ray crystallography. The most representative compounds were screened against M. tuberculosis H37Rv strain and showed moderate activity, compared to isoniazid and ethambutol, in the range of 62.5-125 A mu g/cm(3).