Abstract
Aurasperone C (III) shows properties closely related to those of aurasperone B (II) and gave dianhydro compound (V) on hydrochloric acid treatment. Partial methylation of (V) with methyl iodide afforded a monomethyl ether identical with aurasperone A (I).
NMR studies, including solvent induced methoxyl shifts, indicate the structure of (III) to be 2, 2'-dimethyl-2, 2', 5, 5'-, 8-pentahydroxy-6, 6', 8-trimethoxy-7, 10'-bi [2, 3-dihydro-4H-naphtho [2, 3b] pyran-4-one], in which the 8-methoxyl of aurasperone B is replaced by a hydroxyl group.
