D- -altrose

D Altrosan is converted to D altrose by dilute aqueous acid Suggest a reasonable mecha nism for this reaction... 

D-Allose D-Altrose D-Glucose -Mannose D-Gulose D-ldose -Galactose D-Talose... 

Draw Haworth structures for the two possible isomers of D-altrose (Figure 7.2) and D-psicose (Figure 7.3). 

Intramolecular cycloadditions of chiral nitrones provide a useful tool for the preparation of bioactive heterocyclic compounds.63 Shing et al. demonstrated that 1,3-dipolar cycloaddition of nitrones derived from 3-0-allyl-hexoses is dependent only on the relative configuration at C-2,3, as shown in Scheme 8.16. Thus 3-0-allyl-D-glucose and -D-altrose (both with threo-configuration at C-2,3) produce oxepanes selectively, whereas 3-O-allyl-D-allose and -D-man-nose (both with erythro-configuration at C-2,3) give tetrahydropyranes selectively.80... 

If the data obtained on the dehydration of the 2-(aWo-polyhydroxy-alkyl)benzimidazoles31 is considered, it is to be expected that no inversion occurs in the configuration of the carbon atom next to the furan ring. If this is so, the anhydride should have formula XXXIV. With the object of deciding this question, researches are being carried out32 on the reaction of ethyl acetoacetate with 3,6-anhydro-n-glucose and with D-altrose. 

See also Aluminum entries D-Altrose, 4 698 Alum. See Aluminum sulfate Alum cake, 2 357... 

Synthese der 2-Thio-D-glucose und einiger 3-Thio-D-altrose-Derivate, by E. Hardegger and W. Schiiep, Helv. Chim. Acta, 53 (1970) 951-959. 

Figure 9.3 Stereoisomers of the D-aldoses. D-Ribose and D-arabinose differ only in their configuration about a single carbon atom (carbon 2) and are examples of epimers. Diastereoisomers are stereoisomers which are not enantiomers of each other but are chemically distinct forms, the eight D-hexoses being examples. Some, however, are also epimers of each other, for example D-allose and D-altrose. The number of aldoses in the L series is equal to that of the d series and each compound is an enantiomer of one in the other series.

Arabinose isomerase [EC 5.3.1.3] catalyzes the interconversion of D-arabinose and D-ribulose. The enzyme will also utilize L-fucose and more slowly utilize L-galactose and D-altrose as substrates. L-Arabinose isomerase [EC 5.3.1.4] catalyzes the interconversion of L-arabinose and L-ribulose. 

A. C. Richardson and H. O. L. Fischer, Cyclization of dialdehydes with nitromethane, Part VI. Preparation of 3- amino-1,6-anhydro-3-deoxy-p-D-gulose, -P-D-altrose and -p-D-idose derivatives and their characterization by means of inversion of mesyloxy groups,./. Am. Chem. Soc., 83 (1961) 1132-1139. 

L. Hough, A. A. E. Penglis, and A. C. Richardson, The synthesis of derivatives of 3-amino-2,3-dideoxy-2-fluoro-D-altrose, Carbohydr. Res., 83 (1980) 142-145. 

D-Talitol has been prepared by the reduction of D-talonolactone or D-talose. Recently, an improved method of preparation, the hydrogenation of D-altrose in high yield, has been described. ... 

Williams and J. K. N. Jones have shown that the dithioacetals of aldopentoses and aldohexoses may be separated as their acetates.472 In certain cases, however, isomers were not separated (for example, D-altrose and D-talose), but reduction of the dithioacetal to the 1-de-oxyalditol permitted resolution of the acetates. The method is not suitable for quantitative determinations, but it does preserve the... 

These values indicate that the rate of reaction of D-altrose with D-tartrate is the same as that of L-altrose with L-tartrate and that other rates pair up similarly. Similar data were obtained for some other pairs of enantiomers. Unfortunately no kinetic data are available on these systems. 

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