Abstract
New visnagin-9-sulfonamide derivatives 3 and 4a-c were synthesized through the reaction of visnagin-9-sulfonyl chloride 2 with amino compounds. Acetylation of compounds 4b and 4c gave the monoacetyl and diacetyl derivatives 5 and 6, respectively. Diazotization reaction of compound 4b afforded the corresponding benzotriazole derivative 8. Pyrazole and thiopyrimidine derivatives 9 and 10 were obtained via the opening of pyrone ring upon reaction of compound 3 with hydrazine hydrate and thiourea, respectively. In addition, hydrolysis of compound 3 with potassium hydroxide furnished the visnaginone derivative 11 which used as starting material for synthesize benzofuran derivatives 12-14 and bergaptene derivatives 15-17. The synthesized compounds were tested for antimicrobial activity. Furochromone derivatives 3, 4a-c, 5, 6 and 8 (visnagin-9-sulfonamide derivatives) demonstrate moderate antibacterial and antifungal activities compared with the antibacterial and antifungal activites of the standard drugs. Benzofuran derivatives 11-14 (visnaginone derivatives) showed the lowest antimicrobial activity among all the compounds investigated in this study. Furocoumarin derivatives 15a, b, 16 and 17 (furobenzopyransulfonamide [bergaptensulfonamides]) are moderately active against all the tested strains.