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Altrose, configuration

The sugar has been suggested as a source for D-altrose and D-ribose since it is easily oxidized by oxygen in alkaline solution to D-altronic acid calcium D-altronate is oxidized by hydrogen peroxide and ferric acetate to D-ribose. These reactions also provide proof for the assignment of the D-altrose configuration to the sugar (122). [Pg.102]

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... [Pg.255]

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. [Pg.112]

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. 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.
For the first time, DFT theory has been applied to a study of diastereofacial selectivity in 1,3-dipolar cycloadditions of nitrones to di-3,4-dimethylcyclobutene. ° The stereochemical outcome of the INAC reactions of nitrones (49) and (52) derived from 3-(9-allyl-D-hexoses is dependent only on the relative configuration at C(2,3), and thus 3-(9-allyl-D-glucose (48) and -o-altrose (threo configuration) afford oxepanes (50) selectively whereas 3-O-allyl-D-allose (51) and -D-mannose (erythro configuration) give tetrahydrofurans (53) and (54) selectively (Scheme 18). frani-2-Methylene-... [Pg.461]

See other pages where Altrose, configuration is mentioned: [Pg.1285]    [Pg.255]    [Pg.51]    [Pg.58]    [Pg.60]    [Pg.51]    [Pg.58]    [Pg.60]    [Pg.129]    [Pg.1285]    [Pg.255]    [Pg.51]    [Pg.58]    [Pg.60]    [Pg.51]    [Pg.58]    [Pg.60]    [Pg.129]    [Pg.150]    [Pg.388]    [Pg.15]    [Pg.53]    [Pg.1039]    [Pg.14]    [Pg.52]    [Pg.174]    [Pg.185]    [Pg.639]    [Pg.149]    [Pg.152]    [Pg.19]    [Pg.40]    [Pg.253]    [Pg.58]    [Pg.254]    [Pg.255]    [Pg.356]    [Pg.639]    [Pg.46]    [Pg.91]    [Pg.10]    [Pg.27]    [Pg.38]    [Pg.38]    [Pg.41]    [Pg.47]    [Pg.54]    [Pg.59]    [Pg.125]    [Pg.29]   
See also in sourсe #XX -- [ Pg.982 ]

See also in sourсe #XX -- [ Pg.982 ]

See also in sourсe #XX -- [ Pg.871 ]

See also in sourсe #XX -- [ Pg.1009 ]



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Altrose

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