Paolo Tavecchia

Analysis of madurose and other actinomycete whole cell sugars by gas chromatography

Abstract The biomass of Actinomadura madurae, Microtetraspora glauca and Planobispora rosea was hydrolyzed, the released sugars were reduced, acetylated and the resultant alditol acetates analysed by gas chromatography (GC) and GC-mass spectrometry. An unidentified sugar occurring in all strains was confirmed to be madurose ( 3-O- methyl - d - galactose ) by comparison with synthetically prepared madurose which was authenticated by proton nuclear magnetic resonance spectroscopy ( 1 H-NMR). The occurrence of this sugar is in agreement with current actinomycete taxonomy.

Degradation studies of antibiotic MDL 62,879 (GE2270A) and revision of the structure

Abstract Fragments of the thiopeptide antibiotic MDL 62,879 (GE2270A) were prepared under mild degradation conditions. Their structures were determined by spectroscopic techniques and by comparison to synthetic reference thiazolyl dipeptides. The two thiazolyl amino acids have stereocenters with S configurations and their sequence is reversed with respect to the structure previously proposed for MDL 62,879.

CHEMICAL MODIFICATION OF THE GE 2270A MACROCYCLE (MDL 62,879)

Abstract Controlled acid hydrolysis of compound 2 resulted in the selective opening of the macrocycle while in basic condition a retro-aldol reaction occurred at the level of phenylserine thiazole. Compound 2 can be easily prepared from the natural antibiotic MDL 62,879. All the compounds prepared resulted less active than MDL 62,879.