Total Synthesis of Premithramycinone H and Related Anthrapyran Antibiotics

Two approaches are described for the preparation of 2‐(1′,3′‐dioxoalkyl)‐substituted 1‐hydroxyanthraquinones 10a−d and 20a−c, which were cyclized in a biomimetic‐type reaction to the anthra[1,2‐b]pyran skeletons 11a−d and 21a−c of the heydamycin‐ or pluramycin‐type antibiotics. Cleavage of the methyl ethers afforded the natural product premithramycinone H (2). The simple derivative 11b showed inhibition of the A431 cell line in µmolar concentrations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)