Structural elucidation of A-74528, an inhibitor for 2′,5′-phosphodiesterase isolated from Streptomyces sp.

The structure of A-74528 was elucidated by NMR techniques including natural abundance INADEQUATE to be a highly fused polyketide with a side-chain branching site that never appeared before from the nature. The relative configuration was elucidated by the analyses of NOEs and assessment of dihedral angles predicted by QUANTA/CHARMm computations and coupling constants.