A35512, A COMPLEX OF NEW ANTIBACTERIAL ANTIBIOTICS PRODUCED BY STREPTOMYCES CANDIDUS
II. CHEMICAL STUDIES ON A35512B
1980 年 33 巻 12 号 p. 1407-1416
詳細
1980 年 33 巻 12 号 p. 1407-1416
The glycopeptide antibiotic A35512B was isolated from Streptomyces candidus NRRL 8156 as the major active factor. Chemical degradation studies showed that mild acid hydrolysis resulted in the release, one molecule each, of four neutral sugars: rhamnose, fucose, glucose and mannose, as well as the liberation of a complex peptide core which retained all the amino acids and from which 3-amino-2, 3, 6-trideoxy-3-C-methyl-L-xylo-hexopyranosae, new amino sugar, was isolated (2). Oxidative degradation of A35512B resulted in the isolation of a chlorodiphenylether (5), dimethyl 4-methoxyisophthalate (7) and methyl 3, 5-bis-(4-methoxycarbonylphenoxy)- 4-methoxybenzoate (6). The structure of 5 could not be conclusively elucidated but was shown to be either 5-chloro-2', 3-dimethoxy-2, 5'-dicarbomethoxy diphenylether (5a) or 2-chloro-2', 3-dimethoxy-5, 5'-dicarbomethoxy diphenylether (5b) by physical methods. This halogenated fragment was shown to arise from oxidation of constituent amino acid (10) which has the aromatic substitution pattern of fragment (5a or 5b). Base hydrolysis resulted in theisolation of a phenanthridine (9) which arose from 2', 4, 6-trihydroxybiphenyl-2, 5'-diyldiglycine. These chemical degradation studies on A35512B showed that this antibiotic is closely related to the ristocetin class of antibiotics.
