CAN-Mediated Oxidations for the Synthesis of Xanthones and Related Products
作者:Myron M. Johnson、Jeremy M. Naidoo、Manuel A. Fernandes、Edwin M. Mmutlane、Willem A. L. van Otterlo、Charles B. de Koning
DOI:10.1021/jo101873v
日期:2010.12.17
Reaction of (2,4,5-trimethoxyphenyl)(2-hydroxyphenyl)methanone with ceric ammonium nitrate furnished the xanthone, 2,3-dimethoxy-9H-xanthen-9-one. Under the same conditions the related (1,4-dimethoxynaphthalen-2-yl)(2-hydroxyphenyl)methanone resulted in the formation of 12a-methoxy-5H-benzo[c]xanthenes 5,7(12aH)-dione. Other examples of this novel transformation are also outlined.
(2,4,5-三甲氧基苯基)(2-羟苯基)甲酮与硝酸铈铵的反应提供了x吨酮2,3-二甲氧基-9 H-黄原-9-酮。在相同条件下,相关的(1,4-二甲氧基萘-2-基)(2-羟苯基)甲酮导致形成12a-甲氧基-5 H-苯并[ c ]黄嘌呤5,7(12a H)-二酮。还概述了此新颖转换的其他示例。
The synthesis of xanthones, xanthenediones, and spirobenzofurans: Their antibacterial and antifungal activity
作者:Justin J. Omolo、Myron M. Johnson、Sandy F. van Vuuren、Charles B. de Koning
DOI:10.1016/j.bmcl.2011.09.088
日期:2011.12
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 mu g/mL) against C. albicans and C. neoformans, respectively. Furthermore, dione 10 displayed the most significant activity (3.6 mu g/mL) against both yeasts. (C) 2011 Elsevier Ltd. All rights reserved.