Kijanimicin. Part 3. Structure and absolute stereochemistry of kijanimicin

Abstract

Kijanimicin, a novel antibiotic from Actinomadura kijaniata nov. sp. SCC1256 (ATCC 31588), has been shown by chemical degradation, spectroscopic studies, and X-ray crystallographic studies to have a unique tetronic acid structure. The molecule contains a branched chain tetrasaccharide moiety consisting of three units of 2,6-dideoxy-α-L-ribo-hexopyranose and one unit of 2,6-dideoxy-4-O-methyl-β-L-ribo-hexopyranose. The molecule also contains a novel nitrosugar, namely 2,3,4,6-tetradeoxy-4-methoxy-carbonylamino-3-C-methyl-3-nitro-β-D-xylo-hexopyranose (D-kijanose), which is the third nitrosugar to be isolated from an antibiotic. The structure of L-rubranitrose is revised to D-rubranitrose. Evidence for the total structure, the absolute stereochemistry, and the solution conformation of kijanimicin is presented.