STEREOCHEMISTRY OF THE MACROLACTINS

The macrolactins are a group of six 24-membered ring lactones isolated from a taxonomically-undefinable deep sea bacterium. Macrolactin A, the parent aglycone, shows a number of interesting biological activities, including the protection of T-lymphoblast cells against human HIV viral replication. Herein we report the stereochemistries of macrolactin B and macrolactin F, which were determined by a combination of C-13-acetonide analysis using isotopically enriched acetone, oxidative degradation, and chemical correlation. Macrolactins B and F were found to have the same stereochemistry at each of the common stereogenic centers, and so we expect that macrolactin A, the aglycone of macrolactin B, has the stereochemistry 7S,13S,15R,23R.