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Secondary Metabolites by Chemical Screening, 22. Gabosines, New Carba‐sugars From Streptomyces
Author(s) -
Bach Gabriela,
BreidingMack Sabine,
Grabley Susanne,
Hammann Peter,
Hütter Klaus,
Thiericke Ralf,
Uhr Hermann,
Wink Joachim,
Zeeck Axel
Publication year - 1993
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199319930143
Subject(s) - chemistry , derivatization , absolute configuration , stereochemistry , cyclohexanone , specific rotation , chemical transformation , streptomyces , chemical structure , secondary metabolite , primary (astronomy) , ketone , chemical shift , secondary metabolism , organic chemistry , biochemistry , biosynthesis , high performance liquid chromatography , bacteria , enzyme , physics , astronomy , gene , catalysis , biology , genetics
Chemical screening of different Streptomycetes strains resulted in the detection, isolation, and structure elucidation of a number of novel carba‐sugars. The constitution of these secondary metabolites, named gabosines A to K ( 1 to 11 ), was deduced from spectroscopic data as well as chemical transformation reactions. The gabosines exhibit a basic C 7 skeleton and can be characterized as hydroxylated branched cyclohexanone derivatives, which show structural similarities to carbohydrates deriving from secondary metabolism. The configuration fo the gabosines (absolute stereochemistry for 1 , 4 , 5 , and 6 ; relative configuration for the remaining metabolites) was determined by derivatization with chiral acids (Helmchen's method), NMR spectral analysis, as well as by a comparison of optical rotation values with those of the already known gabosines B ( 2 ) and C ( 3 ). The new term “ketocarbasugars” is used to characterize a typical ketone containing subgroup of carba‐sugars originating from microbial sources. The well available natural gabosines can be used as suitable chiral building blocks.