Abstract

Background: Pyrazole, oxazole and pyrimidine are nitrogen containing heterocycles which possess very good binding efficiency with receptor or proteins. Due to this effect it can be work as antitubercular agents with active substituents. The objective of this paper is clubbed the heterocycles to enhance their antitubercular potency. Methods: The active substituted pyrazole aldehydes were synthesized by reaction of phenyl hydrazine with different acetophenone followed by Vilsmeier-Haack formylation reaction. The isoxazole and aminopyrimidines were prepared by condensation of various chalcones with hydroxyl amine hydrochloride and guanidine hydrochloride respectively. The structures of the newly synthesized compounds were characterized by ¹H-NMR, Mass, IR and elemental analysis data. All the newly synthesized compounds were screened for their antibacterial activity against Gram-positive S.pyogenus and Gram negative E.coli, Paeruginosa, S.aureus and antitubercular activity against mycobacterium tuberculosis H37Rv. Results: Oxygen containing substituent in aromatic ring or heterocycles as a substituent were enhancing the antitubercular activity as compared to the other substituents. Ethoxy group present as a substituent in aromatic ring shows minimum inhibition concentration as compared to others. Conclusion: X-ray crystallographic study enhances that E-isomer formed in case of chalcones. The electron withdrawing group such as fluorine and chlorine enhancing the activity of Isoxazole and Pyridine as compare to the chalcones. Electron donating group such as ethoxy is increase the potency of the compounds at para position.

Keywords: Antitubercular screening, Antimicrobial screening, Aminopyrimidines, Isoxazoles, Chalcones.