On the Structure Elucidation of Niphimycin, Part I. Purification and Characterization of the Niphimycins Iα and Ib̃; Degradation by Nitric AcidFrom a sample of niphimycin the pure components, niphimycin Iα and Ib̃, were isolated by column chromatography and droplet counter‐current chromatography. They were characterized by UV., IR.,1H‐NMR. (300 MHz) and13C‐NMR. spectra. A vigorous degradation of niphimycin with nitric acid, followed by esterification with diazomethane, gave a complex mixture, from which many components could be isolated and identified. Several of the degradation products were synthesized, one of them (dimethyl 2,4‐dimethyladipate) in a stereospecific manner, establishing the configuration of two of the centers of chirality of niphimycin.Niphithricin was identified with copiamycin and yielded with nitric acid a degradation mixture very similar to that from niphimycin. The structures of the degradation products are in good agreement with a macrolide‐type structure of niphimycin and copiamycin.Further work for structure elucidation of niphimycin and copiamycin i