Synthesis, antibacterial activity evaluation and QSAR studies of novel dispiropyrrolidines

A series of novel dispiropyrrolidines have been synthesized through 1,3-dipolar cycloaddition of an azomethine ylide generated from sarcosine and isatin with the dipolarophile 3-benzylidene-1-methyl-pyrrolidine-2,5-dione. Their antibacterial activity was evaluated against Bacillus subtilis NCIM 2718, Staphylococcus aureus NCIM5021, Salmonella typhi NCIM2501, Pseudomonas aeruginosa NCIM 5029 and Proteus vulgaris NCIM2813 by two fold dilution method. Compound 6e exhibits reasonably good activity and compound 6c exhibits poor activity against all the organisms. The QSAR’s were developed for all antibacterial activities. The models had either one or two descriptors (r2 = 0.81–0.97, radj2=0.75–0.96, q2 = 0.57–0.92, F-ratio = 12.73–162.76). Topology, shape, charge distribution and hydrophobic nature of the molecules had pronounced effect on their antibacterial activity.