Nuclear Magnetic Resonance and Structure of Hygromycin (Homomycin)

Abstract

An antibiotic, hygromycin (homomycin), was studied by proton and carbon magnetic resonances as well as chiroptical techniques to determine the absolute configuration since some aspects have been remained uncertain. The location of a methylene substituent is concluded on C-4 and C-5 position of neoinosamine-2 by the cuprammonium method and the exciton chirality rule. The proton NOE experiment suggests a trans-configuration of the 2-methyl-caffeic acid moiety. A rather unusual glycosidic stereochemistry of cis β-D-arabino-hexofu-ranoside configuration is determined by recently advanced CMR techniques and the absolute structure of the antibiotic has been assigned as I.