Heptulose, D-gluco

Thus, the 2-nitroethanol synthesis results in the addition of two carbon atoms to an aldose sugar to produce two higher-carbon ketose sugars epimeric at carbon 3. While the synthesis is general in nature, the two ketoses produced from any one aldose are seldom as readily separable as is fortunately the case with D-mannoheptulose and D-gluco-heptulose. However, the newly developed techniques of adsorption and partition chromatography will undoubtedly be of service for the more difficult separations. 

S) Ketose Structures.—The equilibria for ketoses differ markedly from those of aldoses, because the hydroxymethyl group attached to the anomeric carbon atom tends to assume an equatorial position. Maintenance of the anomeric hydroxymethyl group in the equatorial position keeps the anomeric hydroxyl group in the axial position. With a-D-sorbose (a-D-xylo-hexulose) and a-D-gluco-heptulose in the CA conformation, all large groups except the anomeric hydroxyl... 

Synthesis from aldonolactones The synthesis of p-homonojirimycin (2) from tetra-(9-benzyl-D-glucono-1,5-lactone (56) (Scheme 8) was achieved by treatment of the latter with (methoxymethoxy)methyl lithium to give the a-D-gluco-heptulose derivative 57, which underwent reduction with LiAlITj to produce a mixture of heptitols 58 (1 1 ratio). Oxidation of 58 using Swern oxidation (DMSO-TFAA) gave the heptodiulose 59. Compound 59 was immediately submitted to reductive amination using ammonium formate in the presence of sodium cyanoborohydride to produce 60 in 50% yield from 58. Removal... 

Epimerization at the third carbon or formation of ketoses that have a carbonyl group at carbon 3 may take place. These reactions explain the formation of D-psicose from D-glucose (85) D-gluco-heptulose from D-glycero-D- aZa-heptose (86), the interconversions of D-sorbose and D-galactose (78),... 

B) Heptoses and heptuloses D-Sedo(altro)heptulose 30, D-manno-heptulose 33, D-glycero-D-guloheptose 8, D-glucoheptulose 20, L-gluco-heptulose 8, L-galactoheptulose 40. 

The C-n.m.r. spectra of nine heptoses and all the heptuloses have been measured and most of the resonances assigned, and hence the furanose and pyranose compositions were determined. For the heptoses the compositions were similar in the main to those for the homomorphous hexoses, while the compositions of the heptuloses varied from 100% o -pyranose for the D-gluco isomer to mainly furanose, e.g, ... 

Heptose, o-glycero-v-ghico-, 293 D-glycero-D-gulo-, 83 D-glycero-D-manno-, 293 Heptosides, hydrolysis of, 43 Heptulose, v-gluco-, 83, 293 B-manno-, 293... 

The natural occurrence of a heptulose together with a related heptitol would appear to be a general feature, since sedoheptulose is accompanied by (a) volemitol in the root stock of Primula elatior (L) Hill, and (b) j3 -sedoheptitol (D-glycero-jj-gluco-heptitol) in the leaves and stems of... 

N-Demethyldesalicetin-2-(4 -aminosalicylate), D-388 7-Deoxy-D-g/ycero -u-gluco -heptose, D-160 7-Deoxy-L-g/ycera -u-gluco -heptose, D-161 7-Deoxy-fl/tra-2-heptulose, D-167 7-Deoxysulfurmycinone, S-99 2 -Deoxy-5-(trifluoromethyl)uridine, D-381 Desalicetin 2 -(4-aminosalicylate), D-388 Desalicetin, D-388 Detorubicin, D-391... 

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