The synthesis of xanthones, xanthenediones, and spirobenzofurans: their antibacterial and antifungal activity.
Exposure of the phenol, (5-bromo-2-hydroxyphenyl)(2,4,5-trimethoxyphenyl)methanone 18 to ceric ammonium nitrate (CAN) resulted in the formation of 7-bromo-3,4a-dimethoxy-2H-xanthene-2,9(4aH)-dione 19 and 5-bromo-2',5'-dimethoxy-3H-spiro[benzofuran-2,1'-cyclohexa[2,5]diene]-3,4'-dione 20. The brominated spirobenzofuran 20 was then subjected to Suzuki-Miyaura reactions to give six derivatives 22a-f. These compounds, related diones and xanthones displayed mostly noteworthy antimicrobial activity, particularly towards the yeasts Cryptococcus neoformans and Candida albicans. Diones 15 and 30 displayed significant activity (7.8 μg/mL) against C. albicans and C. neoformans, respectively. Furthermore, dione 10 displayed the most significant activity (3.6 μg/mL) against both yeasts.
Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, PO Box Wits 2050, South Africa.
Justin J
JJ
Omolo
Myron M
MM
Johnson
Sandy F
SF
van Vuuren
Charles B
CB
de Koning
D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D016227:Benzoquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D002176:Candida albicans / Q000187:drug effects*; D003455:Cryptococcus neoformans / Q000187:drug effects*; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D044004:Xanthones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D001572:Benzofurans; D016227:Benzoquinones; D013141:Spiro Compounds; D044004:Xanthones; C434164:spirobenzofuran