Reassignment of the 13C NMR spectrum of minomycin
Yoshito Takeuchi*, Yoko Imafuku, and Miki Nishikawa
Department of Chemistry, Faculty of Science, Kanagawa University 2946 Tsuchiya, Hiratsuka, Japan 259-1293
E-mail: yoshito@chem.kanagawa-u.ac.jp
(received 08 Apr 03; accepted 23 Oct 03; published on the web 31 Oct 03)
Abstract
1H and 13C NMR spectra of minomycin were determined and a full assignment was carried out with the aid of HMQC, HMBC and other techniques. It was shown that the previous assignment for 13C-NMR signals required some correction.
Keywords: 13C NMR, 1H NMR, HMBC, HMQC, antibiotics, isotope shift
Introduction
As an extension of our synthetic and structural studies of organogermanium compounds1, we were interested to study the changes of physiological activity induced in antibiotics by the introduction of a germanium-containing moiety.
The first antibiotic we chose for this purpose was minomycin (minocycline) hydrochloride (1). It is essential to have a full assignment of the 1H and 13C NMR spectra of 1 in order to elucidate the structure of the reaction products of germylation.
OHOOHOOHOHNCH3H3CNCH3H3CHHHHCONH212344a55a66a7891010a1111a1212a
1
Figure 1
Two papers have so far been published on the NMR spectra of 1, one by Nilges et al.2 on 1H NMR, and another by Mazzola et al.3 on 13C NMR spectra. In the paper by Nilges et al.2, as well
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