Synthesis of a series of new Schiff bases having heterocyclic moiety and their microbial activity

Heterocyclic compounds were synthesized using water based method. These were synthesized by reacting different aldehydes namely benzaldehyde, 2-chloro benzaldehyde, 4-chloro benzaldehyde, 2-nitro benzaldehyde and 3-nitro benzaldehyde with different heterocyclic amines like 4-amino phenazone and 4-amino-1,2,4-trizole. This method constitute an energy-efficient and environmentally benign greener chemistry version of the classical condensation reactions for Schiff base formation. These compounds were characterized by IR, H-1 NMR and C-13 NMR spectroscopic techniques. The colored Schiff bases (1, 3, 5, 7 and 9) were also characterized by UV spectra. Synthesized anils were screened for their microbial activity against Mesorhizobium sp. (SB 271), S. aureus, E. coli and Pseudomonas sp. (PGPR 3). Maximum growth was inhibited by compounds 6 and 8 against Mesorhizobium sp. Compounds 1, 3, 4 and 10 showed maximum inhibited growth for S. aureus. Maximum Pseudomonas sp. growth was inhibited by compounds 2, 4 and 9. Maximum E. coli growth was inhibited by the compounds 2, 5 and 10. However, these compounds showed less microbial activity as compared to streptomycin except the compound 9 recorded higher microbial activity than streptomycin against Pseudomonas at 5000 ug/ml. All other anils including this 9 exhibited less activity than streptomycin at all the concentrations.