Heptoses chromatography

Heptoses, chromatography of, 287-289 from bacterial polysaccharide, 302 in bacteria, 286, 287 methylated, 288 periodate oxidation of, 288, 289 —> n-glyeero-D-galacto-, 320 —, v-glycero-D-manno-, 288, 320 —, D-glycero-L-numno-, 287, 319, 320, 326 —, h-glycero-v-manno-, 277, 278, 310, 320 Heptulose, D-altro-, 286 1,7-diphosphate, 240-248, 255 7-phosphate, 241-245, 247 —, o-manno 286 Heptulosonic acid, 3-deoxy-, 251 —, 3-deoxy-D-am5t o-, determination of, 252... 

In alkaline solution, glycolaldehyde gives rise to tetroses.160- 169 Tetroses combine with dihydroxyacetone in alkaline solution to give heptoses, as indicated by the results of paper chromatography.16 43... 

Occurrence and preparation. The major heptose of the LPS of Vibrio cholera Inaba 569B was proved to be D-glycero-h-manno-heptose (47), by isolating the sugar through repeated purification on paper chromatography, and was confirmed by comparison with an authentic sample (synthesized via condensation of nitromethane with D-galactose).246... 

Occurrence and preparation. Begbie and Richtmyer have shown that the dried root of the primose (Primula officinalis Jacq.) contains the heptose 50 among a number of other sugars. It was purified by column chromatography from aqueous extracts of the root.256... 

Occurrence and preparation. In the first report of its occurrence,248 D-glycero-L-galacto-octulose (63) was obtained from the pulp of ripe avocados (Calavo, Hass variety) by extraction and chromatography (see under D-g/ycero-D-ga/acto-heptose). The octulose was also isolated from the dried roots of Primula officinalis Jacq. 

In order to confirm that the stereoselectivity followed Kishi s empirical rule for dihydroxylations, the (Z)- and ( )-aUylic alcohols were prepared using (methoxy-carbonylmethylene)triphenylphosphorane 2 and formylmethylenetriphenylphos-phorane 3, respectively, followed by reduction with diisobutylaluminum hydride. The catalytic dihydroxylation in the presence of osmium tetroxide and N-methyl-morpholine N-oxide (NMO) afforded the D-glycero-isomer 6 from olefin 4 whereas the L-glycero-isomer 9 was obtained, as a major product, from the (F)-isomer 7. Finally, the separation by column chromatography or by protection/deprotection sequences provided the pure D-glycero-o-manno-heptose 10 and i-glycero-D-manno-heptose 11 (Scheme 2.3). 

In 2005, Kosma et al. [9] employed the same alcohols 4 and 7 as intermediates to prepare D-glycero-D-mowwo-heptose-7-phosphate 18 and other heptose derivatives [10]. The phosphorylation of alcohol 4 using the phosphoramidite procedure afforded the 7-O-phosphotriester 15 in 65% yield. The catalytic osmylation of the alkene provided a 1 4 mixture of 16 and 17 in 71% yield. After separation by chromatography, the catalytic hydrogenation of 17 in the presence of 10% Pd/C... 

Addition of 3-Bromopropenyl Esters Indium-mediated acyloxyaUylation of unprotected D-ribose, D-arabinose, D-lyjrose, and D-xylose were reported by Madsen et al. [50], in order to synthesize their corresponding heptosides. As an example, the treatment of D-ribose with 3-bromopropenyl acetate in ethanol at 50 °C in the presence of indium metal afforded the peracetylated polyol 85 in 82%. Only two out of the four possible diastereoisomers were observed with a 1.5 1 selectivity (Scheme 2.22). Deacetylation of the major D-isomer, isolated by flash chromatography, followed by ozonolysis gave the corresponding D-0ycero-D-manno-heptose 10. 

Application of the nitromethane route to L-mannose has furnished a mixture of L-glycero-i.-galacto-heptose (43%) and L-glycero-L-talo-h ptose (12%), which could be separated by ion-exchange chromatography. A synthesis of D-gluco hept-3-ulose (4) from perseitol (3) is shown in Scheme 2 the racemic form of (4)... 

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