Heptitols

The relationships between the naturally occurring heptoses and the corresponding heptitols and hexoses are shown below  

D-Altrose D-Sedoheptulose L-Perseulose L-Galactose. / h-glycero-D-talo-lieptitol L-Gulose — h-glycero-D-gala-Heptitol 

The full arrows represent demonstrated conversions. For galactose and gulose, the arrows with dotted lines represent conversions carried out with the enantio-morphic modifications. 

The configurations of the D-series of some optically active heptitols and the meso forms are illustrated on p. 255. The physical constants of the known heptitols and their acetates, as well as references to their synthesis, are given in Table II. 

64- For a review of the occurrence of these materials and their configuration, see C. S. Hudson, Advances in Carbohydrate Chem. 1, 1 (1945). 

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D-glycero-D-galacto-HepMo not L-p/ycero-D-manno-heptitol... 

C19H23BrO10S 4,5,7-Tri-0-acetyl-2,6-anhydro-l-0-(p-bromophenylsul- fonyl)-3-deoxy-D-gluco-heptitol BACGLO 31 369... 

Hough and Shute57 reported that heating of 1-deoxyl-l-nitro-D-g/ycero-L-manno-heptitol (47) in aqueous solution led to the elimination of water and the formation of C-/3-i>galactopyranosylni-tromethane (48) as the major product. After fractionation of the mother liquors on an anion-exchange resin, they obtained evidence for the formation, albeit in small amounts, of C-a-D-galactopyranosyl-... 

The old condensation38 of 4,6-O-benzylidene-D-glucose with nitromethane in the presence of sodium methoxide to give D-heptitol 42 and cyclic nitromethyl p-D-glucopiranose (44, 5% yield) has recently been revisited. 

This sequence involves a Henry reaction of 41 with nitromethane followed by a dehydration of the resulting acyclic D-heptitol derivative 42 and a Michael intramolecular addition of the resulting nitroolefin 43. 

In a similar fashion it should be a relatively simple task to relate the well-known D-gala-L-manno-heptose (XX) to a-rhamnohexose (XXII)81 through the known 1-desoxy-D-gala-L-mcmno-heptitol (syn., 7-desoxy-L-manno-L- aZa-heptitol) (XXI).81 In. this particular case, however, there is already ample proof of the configuration of the latter sugar (XXII) because nitric acid has been found to oxidize the corresponding aldonic acid to mucic acid.82... 

A-Acyl-1 -amino-2,6,7-trideoxy-2,6-imino-L-glycero-D-manno-heptitols... 

In 1987 2,6-dideoxy-2,6-imino-D-g(ycero-L-gM/o-heptitol (14), a chain-extended derivative of 1-deoxynojirimycin, was synthesized as a potential glucosidase inhibitor [50] and soon thereafter extracted from the leaves of the Panamesian plant Omphalea diandra L [51]. Coined a-homonojirimycin by the discoverers, this novel type of inhibitor exhibited pronounced activity against gluco-... 

The biological activity of the natural product a-homonojirimycin (2,6-dideoxy-2,6-imino-D-glyccro-L-gu/o-heptitol, 14) as a glucosidase inhibitor [50]... 

Certain synthetic heptitols that could not be separated by paper chromatography or by electrophoresis have been separated as their O-trimethylsilyl derivatives.404 The procedure of reductive, alkaline hydrolysis, much used in glycopeptide research, yields alditols that have been estimated as their trimethylsilyl ethers,59,405 and D-glucitol in mammalian nerve has similarly been determined.406... 

D-glycero-L-manno-D-glycero-D-manno-L-glycero-D-manno-Ten isomeric heptitols... 

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