1.2- Dideoxy-galactose

Sucralose is quite stable to heat over a wide range of pH. However, the pure white dry powder, when stored at high temperature, can discolor owing to release of small quantities of HCl. This can be remedied by blending it with maltodextrin (93) and other diluents. The commercial product can be a powder or a 25% concentrate in water, buffered at pH 4.4. The latter solution may be stored for up to one year at 40°C. At lower pH, there is minimal decomposition. For example, in a pH 3.0 cola carbonated soft drink stored at 40°C, there is less than 10% decomposition after six months. The degradation products are reported to be the respective chlorinated monosaccharides, 4-chloro-4-deoxy-galactose (13) and l,6-dichloro-l,6-dideoxy-fmctose (14) (94). 

Synthesis of Chromose A (2,6-Dideoxy-4 G-methyl-n-galactose), J. S. Brimacombe, D. Portsmouth, and M. Stacey, Chem. Ind. (London), (1964) 1758. 

Sarmentose Sedoheptulose Sedoheptulosan Solatriose 2.6- Dideoxy-3-0-methyl-D-xy/o-hexose D-a/froHept-2-ulose 2.7- Anhydro P-D-a/fro-hept-2-ulopyranose a-L-Rhamnopyranosyl-(1 ->2)-[P-D-glucopyranosyl-(1->3)]-D-galactose... 

The first, definitive identification of KDO as a constituent of the LPS from Escherichia colt 0111-B4 (and from its UDP-galactose-4-epi-merase-less mutant, J-5) was reported by Heath and Ghalambor.29 When analyzing their LPS preparations for 3,6-dideoxy-L-xyZo-hex-... 

Deoxy-L-galactose 19, 3-amino-2,3-dideoxy-L-xylo-hexose 20 and L-diginose 21 are synthesized conveniently from the aldehyde 18 (35). 

J. Hill, L. Hough, and A. C. Richardson, Nucleophilic replacement reactions of sulphonates. I. The preparation of derivatives of 4,6-diamino-4,6-dideoxy-D-glucose and -D-galactose, Carbohydr. Res., 8 (1968) 7-18. 

As discussed in Sect. 3.4, the synthon 20 was prepared from the dibromo-heptonolactone, which in turn was obtained from the cheap commercially available D-g(ycero-D-gM/o-heptono-l,4-lactone (Table 1). The other isomeric dibro-moheptonolactones shown in Table 1, which were prepared from the heptonates, obtained from chain extension of o-mannose and o-galactose, respectively, were also converted into unsaturated bromodeoxyheptonolactones. Finally, we obtained 2-0-acetyl-7-bromo-3,7-dideoxy-D-x7(o-hept-2-enono-l,4-lactone and the corresponding D-/yxo-isomer by the Kiliani extension of o-gulose. These substrates were all cyclized to cyclopentane lactones, stereoisomers of 65 [98]. 

A mutant strain of Escherichia coli Y-10, defective in L-rhamnose synthesis, accumulates109 a considerable amount of thymidine diphosphate sugars. Three of them were identified110 as the esters of thymidine 5 -pyrophosphate with 6-deoxy-a-D-xyZo-hexopyranos-4-ulose (28), 6-deoxy-D-glucose, and D-fucose. The fourth component was found to be a 4-acetamido-4,6-dideoxy-D-galactose derivative111,112 (29) it occurs also in Pasteurella pseudotuberculosis102 and its... 

An analogous reaction of UDP-2-acetamido-2,6-dideoxy-D-xy/o-hexos-4-ulose (7d) results in formation of the derivatives of 2-acetamido-2,6-dideoxy-D-glucose and -D-galactose.166 These amino sugars were identified as components of several O-specific polysaccharides (for reviews, see Refs. 95 and 167). 

CDP-6-deoxy-D-xy/o-hexos-4-ulose (7b) serves as a precursor in the biosynthesis of CDP-3,6-dideoxyhexoses28,168 having the d-ribo (paratose, 3,6-dideoxy- D-glucose ), o-xylo (abequose, 3,6-dideoxy- D-galactose ), and d-arabino (tyvelose, 3,6-dideoxy- D-mannose ) configurations. These monosaccharides are characteristic components of O-specific polysaccharides from Salmonella and Yersinia pseudotuberculosis. 

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