On the structure of alisamycin, a new member of the manumycin class of antibiotics.

We have recently reported the taxonomy, production, isolation and biological properties of a new antibacterial antibiotic alisamycin (1) by the fermentation of Streptomyces actuosus (culture number HIL Y-88,31582)1). In this communication wereport the structure elucidation of alisamycin which is a new member of the manumycin group of antibiotics. The physico-chemical properties of alisamycin (1) are shown in Table 1. High resolution FABmass spectrometry of alisamycin (1) showed an (M + H) + ion of mass 521.2276 which corresponded to a formula ofC29H33N2O7. This indicated a molecular formula of C29H32N2O7 for alisamycin (1) and an unsaturation number offifteen. TwoUVabsorption maximaat 276 and 315nm (MeOH) indicated extended unsaturation. Although alkaline pH had only a marginal effect on the UVspectrum, acidification shifted the maximaat 315 nm to 325 nm and increased the absorption intensities at both the wavelengths by about 14%, indicating a keto-enol tautomeric system2). IR frequencies at 3400, 1710 and 1670cm"1 indicated hydroxyl, carbonyl and amide groups and a broad band at 1610cm"1