Stereochemical determination of Archazolid A and B, highly potent vacuolar-type ATPase inhibitors from the Myxobacterium Archangium gephyra.

[structure: see text] The relative and absolute stereochemistry of the structurally unique 24-membered myxobacterial macrolides archazolid A and B, highly potent vacuolar-type ATPase (V-ATPase) inhibitors in vitro and in vivo, was determined on the basis of a combination of extensive high-field NMR studies, including J-based configuration analysis, molecular modeling, and chemical methods.