Glutarimide Antibiotics. IX. The Stereochemistry of the Dihydrocycloheximides and the Configuration of the Hydroxyl Group of Cycloheximide

The structures of the dihydrocycloheximides have been reinvestigated both chemically and by means of n.m.r. spectroscopy. This has resulted in new stereochemical assignments being made to the hydroxyl groups of these compounds and to clarification of their chemistry. By a simple procedure the configuration of the hydroxyl group in cycloheximide has been shown to be (R), and not (S) as originally designated. Application of the method to isocycloheximide and naramycin-B shows that they also have their respective hydroxyl groups in the (R) configuration.