Reassignment of the ¹H NMR spectrum of fusidic acid and total assignment of ¹H and ¹³C NMR spectra of some selected fusidane derivatives

Abstract

Reassignment of the 1 H and 13 C NMR spectra of fusidic acid and the total assignment of lumifusidic acid and some important di-and tetra-hydrofusidic acid derivatives are reported.

Microbial Oxidation of the Fusidic Acid Side Chain by Cunninghamella echinulata

“…The precipitated fusidic acid was filtered, washed acid-free with distilled water, and dried to constant weight in a vacuum desiccator. The NMR and MS data were identical to reported data [ 14 , 15 ].…”

“…Compounds 3 and 4 may be considered as intermediates towards the formation of compound 5 and this is the first report of their formation and structural elucidation. Von Daehne et al reported as “unpublished observations” that compound 2 was chemically synthesized by Godtfredsen and Vangedal via oxidation of fusidic acid with selenium oxide in t -butanol [ 14 ], followed by reduction with sodium borohydride to yield compound 2 . The oxygenation step of the 26-Me and 27-Me diastereotopic ligands in the side chain of fusidic acid using C. echinulata does not exhibit regioselectivity, whereas subsequent oxidation of the mixture of 2 and 3 into the formyl and hydroxycarbonyl fusidic acid derivatives 4 and 5 proceeded regiospecifically at C-26.…”

An antibacterial hydroxy fusidic acid analogue from Acremonium crotocinigenum

“…C-11 was deshielded (d C 68.7, d H 4.37) indicating that an oxygen should be placed here. Furthermore, H-13 (delineated by inspection of the HMQC spectrum) was also deshielded (d H 3.05) suggesting that it was allylic and that an olefinic carbon (C-17) should be placed at the neighbouring carbon, which is typical for fusidic acid metabolites (Rastup-Andersen and Duvold, 2002). The protons of a methyl group (C-18) coupled to C-13 ( 3 J), C-14 ( 2 J) and to a methylene carbon (C-15, 3 J).…”

“…High-resolution ESI-TOFMS in the positive mode suggested a molecular formula of C 29 H 46 O 5 . Signals in the 1 H and 13 C NMR spectra (Table 1) for five methyl singlets, one methyl doublet, four olefinic carbons and a carbonyl of a carboxylic acid (d C 173.8), were indicative of a fusidane class triterpene of the fusidic acid type (Rastup-Andersen and Duvold, 2002).…”

Neuraminidase Inhibitors from marine-derived actinomycete Streptomyces seoulensis

“…The 13 C NMR spectrum of 1 exhibited a total of 29 resonance lines arising respectively from two carbonyl ( δ C 176·2 and 214·7), four olefinic, three quaternary, seven methine (3 oxygenated ones at δ C 72·8, 77·0, and 81·8), seven methylene and six methyl carbons. These characteristic NMR data suggested that compound 1 had a steroidal skeleton as possessed 16‐deacetylfusidic acid γ‐lactone (Rastrup‐Andersen and Duvold ). This assumption was substantiated by a set of 2D NMR experiments ( 1 H‐ 1 H COSY, NOESY, HMQC and HMBC), which allowed the unambiguous assignment of all NMR signals (Table ).…”