3-d][1,3]benzooxazocin-13-one. X-ray crystal structure analysis of compounds 6a and 16a revealed that the cleft angles of the planes of the benzopyran moiety and the p-methoxybenzene ring are 109.4° and 108.6°, respectively. The conformation of the aromatic ring at the bridgehead of 16, 16a and 20 is restricted by the gem-dimethyl groups on the C-9 position and the methyl group on the nitrogen atom
A direct synthesis of racemic demethoxyaflatoxin B2
作者:George A. Kraus、Beth E. Johnston、Jacqueline M. Applegate
DOI:10.1021/jo00019a042
日期:1991.9
Aflatoxin analogue 19 was prepared by a direct sequence involving a novel silver-mediated cyclization to 12, the Michael addition of 16 with 17, and the oxidation of the Michael addition adduct. The overall yield of this six-step route is approximately 11%. The pathway is a flexible one that will permit the synthesis of analogues for toxicological analysis.