Tetronic acids, deoxy

The present contribution centers on stereoselective syntheses of mono- and in particular oligo-saccharides of the 2-deoxy- and the 2,6-dideoxy series as well as some branched-chain species. These are the principal sugar portions in a large number of important natural glycosides, such as the cardiac glycosides (3), the orthosomy-cins (D, the tetronic acids (5), the aureolic acids (6, see below), and the anthracyclines (2, see below), to name just a few. 

The O-antigens of Brucella species are homopolymers of a-l,2-linked 4,6-dideoxy-4-formamido-D-mannopyranose residues in which there may bea-1,3 linkages [102,103], The Yersinia 0 9 antigen is a similar 1,2-linked homopolymer but contains no 1,3 linkages. A related structure Y-acylated by 3-deoxy-L-glycero-tetronic acid in place of the formate group is produced by Vibrio cholerae Inaba and Ogawa strains [104], These structures have been the subject of synthetic work [105-107],... 

The five-carbon isosaccharinic acid, 3-deoxy-2-C-(hydroxymethyl)-DL-glycero-tetronic acid, was obtained from alkali-degraded oligo- and polysaccharides containing fi-( —> 4)-linked D-xylose residues.301... 

Five-carbon Isosaccharinic Acid DL-[3-Deoxy-2-C- (hydroxymethyl)-tetronic acid], (dl-[2,4-dihydroxy -2- (hydroxymethyl) butyric ... 

Deo y-D-glycero-tetronic acid 2-Deoxy-L-g<2/-cero-tetronic acid Z-T)eoxy-t>-glycero- Z-T>eoxy-ij-gly-tetronic acid cero-tetronic acid ... 

A variety of a-amino-polyhydroxy-tetronic and pentonic acids have been synthesized from bromodeoxyaldonolactones. Typically, the 2-broino-2-deoxy-D-xylonolactone (33) gave the epimeric azides (34) as a 1 1 mixture after isolation by chromatography, the D-xylo-azide could be converted to 2-acetamido-2-deoxy-D-xylose (35)... 

Prokaryotic organisms synthesise a primary form of vitamin pyridoxol 5 -phosphate from 1-deoxy-D-xylulose 5-phosphate (l-deoxy-D-t/treo-pent-2-ulose 5-phosphate) and 2-amino-2-deoxy-D-threo-tetronic (2-amino-2-deoxy-D-threonic) acid, known as 4-(phosphohydroxy)-L-threonine or 4-hydroxy-i-threonine 4-phosphate. Phosphohydroxythreonine arises from D-erythrose 4-phosphate, a product of decomposition of D-fructose 6-phosphate. Non-phosphorylated forms (pyridoxal, pyridoxol and pyridoxamine) are produced by hydrolysis of the corresponding phosphates. Animals do not synthesise vitamin Bg de novo, only convert the non-phosphorylated forms in the Hver, erythrocytes, and other tissues into the corresponding phosphates and the individual forms of each other. Pyridoxal 5 -phosphate arises by oxidation of pyridoxol 5Lphosphate and transamination of pyridoxal 5 -phosphate provides pyridoxamine 5Lphosphate. Both these forms of vitamin Bg are catalytically active. Pyridoxal 5 -phosphate... 

---