NMR spectroscopic analysis of new spiro-piperidylrifamycins

Abstract

New spiro-piperidylrifamycin derivatives are presented. These compounds were synthesized from the reaction of 3-amino-4-iminorifamycin S and enantiomerically pure 4-piperidones, which generate diasteroisomeric rifabutin analogues with a new stereocentre at the spiranic carbon. The 1H and 13C NMR spectra of these new compounds, and also the configuration of the new stereogenic centres, were assigned using 2D NMR spectroscopic techniques. A preliminary study of the 1H and 13C NMR spectra of the starting compounds rifamycin S, 3-amino-4-iminorifamycin S and the related rifabutin was also carried out and as a result, their previously published 13C NMR data were corrected. Copyright © 2005 John Wiley & Sons, Ltd.