FACILE SYNTHESIS OF PYRAZOLINE DERIVATIVES DERIVED FROM QUINAZOLIN-4(3H)-ONES AS POTENTIAL BIOLOGICAL AGENTS

Quinazolinone backbone is present in a large number of bioactive substances and is known for their pharmacological activities like anticonvulsant, antimicrobial activity. Pyrazolines are another class of heterocyclic compounds associated with important biological activities like anti-inflammatory, analgesic, antimicrobial activity. In this view, it was proposed to synthesize some novel pyrazolines from chalcones containing quinazolinone nucleus. In the current investigation, anthranillic acid was condensed with acetic anhydride to give 2-methyl-3,1-benzoxazin-4-one which on reaction with m-amino acetophenone produces 2-methyl-3-(3-acetylphenyl)quinazolin-4(3H)-one. This compound on further reaction with various substituted aldehydes generates 2-methyl-3{3-[3-substitutedprop-2enoyl]phenyl}quinazolin-4(3H)-one (chalcones). Chalcones were used further and condensed with thiosemicarbazide to synthesize 5-substituted-3-[3-(2methyl-quinazolin-4(3H)-one-3-yl)phenyl]4,5-dihydro-1H-pyrazole-1-carbothioamide. The synthesized compounds were screened for their antibacterial, antifungal and antitubercular activity by standard methods. The results suggest that the compounds exhibit significant antibacterial, antifungal and antimycobacterial activity against B. cereus, S.aureus, E. coli, Candida albicans and M. tuberculosis. Streptomycin, tetracycline, miconazole and rifampin were used as standard drugs. The structures of the synthesized compounds were confirmed using analytical and spectral techniques (IR, 1 HNMR and Mass spectral data).