Synthesis of Novel Nitro Substituted Benzothiazole Derivatives and Antifungal Activity against Aspergillus niger

Author(s): Akhilesh Gupta

Most alarming of allarethe infection that caused byAspergillus (A) niger,it was reported that re-sistance is developing for all currently available drugs; hence, current trends suggested that there is a requirement to develop a new replacement drug which is effective against resistant fungi having lesser toxicity as well as econom-ical also. In view of the requirement benzothiazole nucleus containing compounds bearing nitro group substitution planned to synthesize and evaluate for antifungal activity againstA.niger.C-6 nitro-substituted benzothiazole de-rivatives were synthesized by reaction of 3-chloro-4-nitroaniline with potassium thiocyanate under temperature control and presence of bromine in glacial acetic acid and ammonia. Substitutednitrobenzamidesthen synthesized by condensation of,7-chloro-6-nitro-1,3-benzothiazol-2-aminewith 2(3or4)-nitrobenzoylchlorideacid in presence of dry pyridine and acetone. Finally, newly synthesized derivatives (N-01 toN-09) were synthesized through replacing of chlorine ofnitrobenzamideby reaction with 2-nitroaniline, 3-nitroaniline, and 4-nitroaniline in presence of DMF. Analytical characterization was performed by TLC, melting point, IR and NMR spectroscopy. Antifungal activity was performed againstA. nigerby cup plate method (diffusion technique) using griseofulvin as standard. Com-pound N-03 showed potent antifungal activity againstA. nigerwhile compound N-05, N-08 and N-09 showed mod-erate inhibitory activity at both concentrations 50μg/ml and 100μg/ml as compared to standard. In the present work efforts have been made to synthesized C-6 substituted nitro benzothiazole derivatives and screened for antifungal activity. Compound N-03 found as most active againstA. niger.


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