STUDIES ON POLYOXINS, ANTIFUNGAL ANTIBIOTICS .13. STRUCTURE OF POLYOXINS

Polyoxins A-L were found to be a new class of peptide nucleosides having the structures shown in Scheme I. Hydrolytic degradation of polyoxins afforded three groups of unusual α-L-amino acids, i.e., 1-(5′-amino-5′-deoxy-β-D-allofuranuronosyl)-5-hydroxymethyluracil (polyoxin C) or its three nucleobase analogs, 5-O-carbamoyl-2-amino-2-deoxy-L-xylonic acid or its 3-deoxy analog, and 3-ethylidene-L-azetidine-2-carboxylic acid. These structures were established on chemical and spectroscopic evidence. 5 ′-Aminofuranuronoside common to all polyoxins constitutes a nucleoside with α-amino acid nature. Sequence analysis showed polyoxins are di- or tripeptide of these moieties. The structures so elucidated embody all the interesting chemical features of polyoxins. The hypothetical biochemical significance of the structure was also discussed. © 1969, American Chemical Society. All rights reserved.