Dactylocyclines, novel tetracycline derivatives produced by a Dactylosporangium sp.. III: Absolute stereochemistry of the dactylocyclines

The dactylocycline antibiotics were found through circular dichroism measurements, NMR spectroscopy and chemical transformations to possess the usual tetracycline family absolute configuration at carbons 4, 4a, 5a and 12a. The absolute stereochemistry about the C-6 carbon, however, was the reverse of that found with previously investigated tetracyclines.