Antibiotics of the ostreogrycin complex. Part III. The structure of ostreogrycin A. Evidence based on nuclear magnetic double resonance experiments and high-resolution mass spectrometry

Abstract

The n.m.r. spectrum of ostreogrycin A, which contains 35 protons, has been completely analysed by means of double resonance experiments. These experiments permit probable structural units to be built up, which can then be assembled to give the gross structure (XVI), using chemical evidence available only from the hydrolysis of hydrogenation products of ostreogrycin. The structure of one of these hydrogenation products (“perhydro A₁”) is confirmed in some detail by its high-resolution mass spectrum, which is typical of that of a cyclic acyl-peptide.