(Ss)-8-hydroxy-5,6-dideoxy-5-oxoerythronolide B, a shunt metabolite of erythromycin biosynthesis—V

The isolation and structure elucidation of a shunt metabolite of erythromycin biosynthesis, (8S)-8-hydroxy-5,6-dideoxy-5-oxoerythronolide B ( 1a ), is described. NMR and CD data reveal that the title compound and related 5-oxo derivatives ( 5 and 6 ) are conformationally homogeneous with erythronolide B ( 2 ). Consistent with this observation is the hydroxyketone-hemiacetal equilibrium present in the case of 5 . The spectroscopic data further show that 1a , (8S)8)hydroxyerythronolide B ( 12 ), and lankolide ( 13 ) have identical 8S stereochemistry.