Structural studies on the antibiotic vancomycin: evidence for the presence of modified phenylglycine and β-hydroxytyrosine units

Abstract

Chemical and spectroscopic evidence is presented to support the presence of three oxygenated phenylglycine units in the molecule of the antibiotic vancomycin. The glycine (2 mol. equiv.) reported as a product of alkaline hydrolysis of vancomycin is believed to arise from the fission of two chloro-β-hydroxytyrosine units. The ¹H n.m.r. spectrum of a crystalline degradation product, hexa-O-methyl-N-acetyl-CDPII, is in accord with the presence of the above units, as is the ¹³C n.m.r. spectrum (sp³ carbon atoms) of CDPII itself. The presence of two hydroxygroups in hexa-O-methyl-N-acetyl-CDPII is established through the preparation of a bisdinitrobenzoate.