STRUCTURAL STUDIES OF GLYCOPEPTIDE ANTIBIOTIC A35512B. IDENTIFICATION OF THE DIPHENYL ETHER-TYPE BIS(AMINO ACID).

Article abstract of DOI:10.1016/S0040-4020(01)88578-1

A35512B is one of the components of the A35512 complex of glycopeptide antibiotics recently isolated from Streptomyces candidus.Hydrolysis of the aglycone with 6N HCl gave actinoidinic acid (6), and the previously reported Cl-containing diphenyl ether-type bis(phenylglycine) 2.Hydrolysis of the aglycone in 57percent HI gave 6, tris(amino acid) 5b arising from reduction of the β-OH groups of amino acid 5a, and amino acid 7, formed by dehalogenation of 2.Amino acids 2 and 7 were oxidatively degraded to bis(benzoates) 3d and 10.The structures of 3d and 10 were confirmed by independent syntheses.Amino acid 2 is assigned structure 2d rather than the previously proposed structures 2a or 2b.The absolute configuration of 2d was determined as R for the para-hydroxylated ring and S for the meta-hydroxylated ring.