A revised structure for toxyloxanthone B
Abstract
A re-examination of the n.m.r. data for toxyloxanthone B trimethyl ether, and subsequent synthetic work, both show that toxyloxanthone B has the 2,2-dimethylpyranoxanthone structure (2a) and not the 4,4-dimethylpyranoxanthone system (1a) that was pre-previously assigned.