Chemistry of micrococcin P. Part X. Proton magnetic resonance spectrum of dimethyl micrococcinate, and the probable mode of biosynthesis of micrococcinic acid

Abstract

Proton magnetic resonance measurements, while not providing a unique indication of its structure, are compatible with the formulation of dimethyl micrococcinate as 6-(-4′-methoxycarbonyl-2′,4-bithiazolyl-2-yl)-3-(4-methoxycarbonylthiazol-2-yl)-2(2-propionylthiazol-4-yl)pyridine, as required by the X-ray crystallographic study of the derived bis-4-bromoanilide. Micrococcinic acid is probably derived biogenetically from a peptide composed of four molecules of cysteine, one of α-aminobutyric acid, and one of α-aminoadipic acid by ring-closure, dehydrogenation, and an oxidative deamination.