Synthesis of 4-Triazolylamino- and 4-Benzothiazolylamino-3-nitro-2H-[1]-Benzopyran-2-ones and their Antimicrobial Activity

Abstract

Novel substituted benzopyran-2-one derivatives were synthesized by catalytic condensation reactions under reflux conditions. 4-(1,2,4-Triazolyl-3-amino)-3-nitro-2H-[1]-benzopyran-2-ones 4(a-b) were synthesized by condensation of 4-chloro-3-nitro-2H-[1]-benzopyran-2-one (2) and corresponding 3-aminotriazoles 3(a-b). 4-(4’-methoxy-2-benzothiazolylamino)-3-nitro-2H-[1]-benzopyran-2-one (4c), 4-(6’-nitro-2-benzothiazolylamino)-3-nitro-2H-[1]-benzopyiran-2-one (4d) and 4-(6’-fluoro-2-benzothiazolylamino)-3-nitro-2H-[1]-benzopyran-2-one (4e) were synthesized by condensation of 4-chloro-3-nitro-2H-[1]-benzopyran-2-one (2) and corresponding 2-aminobenzothiazole 3(c-e) under reflux reaction conditions. Further, alkali hydrolysis of 4(a-e) afforded the 2-hydroxy-ω-nitroacetophenone (5). Antimicrobial activity of products 4(a-e) against S. aurous, E. coli and Klebsiella were investigated measuring of inhibition zones around the discs which are marked with DMF, concentration 2 mg/mL, 4 mg/mL and 6 mg/mL solutions. Compounds 4c, 4e and 4d were more active against S. aureus. Emphatic activity against E. coli exhibited compounds 4b and 4e, whereas 4c and 4d were more active against Klebsiella.

Keywords

• benzopyran-2-one
• triazolylamine
• benzothiazolylamine
• antibacterial activity