Sibiromycin: Isolation and Characterization

Sibiromycin, possessing strong antitumor activity in animal experiments, is produced by Streptosporangium sibiricum. Sibiromycin can be isolated from culture filtrate using ion-exchange or by solvent extraction. The antibiotic was obtained as a crystalline substance with ultraviolet absorption maxima at 230 and 310 nm, [α]D+525° (in dimethylformamide); the empirical formula-C24H31N3O7. In 1 N hydrochloric acid, sibiromycin is transformed into "the product of acidic inactivation" (PAI), C24H29N3O6. Hydrolysis of PAI with 6 NHC1 affords "the product of acidic hydrolysis" (PAH), C16H14N2O3. Methanolysis of sibiromycin and PAI yields the methylglycoside of a new amino sugar sibirosamine, C8H16NO3 (OCH3). Aqueous alkaline hydrolysis of PAI and PAH affords the crystalline substance C8H9NO.