Allitol preparation

Starting with the same acetal (35), but proceeding by way of the diacetate 40, instead of the dibenzoate 36, it was possible to prepare,51 in high yield, the p-toluenesulfonate 41 by sequential trityla-tion and p-toluenesulfonylation. Compound 41 was then subjected to solvolysis in the presence of sodium acetate in moist N,N-dimethyl-formamide, and the product (42) was successively acetylated and de-tritylated to give 3,4,6-tri-0-acetyl-2,5-anhydro-D-allitol (43). The... 

It is evident that syntheses of the Lespieau type can lead to a great number of polyhydroxy compounds. Wiemann has prepared compounds such as CHsCH2(CHOH)6CH2CH3, which he calls diethyl mannitol. It would seem better to designate this substance a tetra-desoxy decitol or decane hexol since its configuration is not known with certainty. Apparently this type of synthesis leads to symmetrical arrangements of hydroxyl groups, since allitol, dulcitol and D,L-mannitol are the only hexitols that were identified as products. 

Investigation of the inhibitory effects on glycosidases has been carried out for the hydroxylated pyrrolidines [65] and piperidines [73]. Among the pyrrolidines prepared only the l,4-dideoxy-l,4-imino-L-allitol (23) (Scheme 7) and its C-5 isomer showed any remarkable effects. They inhibited lysosomal a-manno-sidase rather than the processing a-mannosidases I and II [65], and their specificity is in accord with the structural requirements of azafuranose analogues of mannose for inhibiting mammalian a-o-mannosidases [80]. 

The isocyanide method of reduction has been applied successfully for preparing a series of diversely protected 1,4-anhydroalditols 188 l,4-anhydro-5-O-tert-butyldimethylsilyl-2,3-0-isopropylidene-D-ribitol (56, 81%), l,4-anhydro-5-0-terf-butyldimethylsilyl-6-deoxy-2,3-0-isopropylidene-D-allitol (57,87%) and -l-talitol (58,87%), 1,4-anhydro-2- 0-rert-butyldimethylsilyl-3,5- 0 -isopropylidene-... 

D-xylitol (59,81%), and 2- O -acetyl-1,4-anhydro-6-deoxy-3,5- 0-( 1,1,3,3-tetraiso-propyldisiloxan-l,3-diyl)-D-allitol (60,77%). The reported yields appeared to be independent of the anomeric configuration of the substrates, prepared in two steps from the corresponding glycofuranosyl azides, via the formamides. 

L-Allulose (LXI) was prepared by Steiger and Reichstein through the oxidative fermentation of allitol (LX) by the sorbose bacterium, Acetobacter xylinum. The product was isolated and purified by means of its crystalline diacetone derivative, of m. p. 57° and - -99 in... 

One of the most efficient methods for the generation of 2,5-dideoxy-2,5-iminogalactitol 16 relies on the fuculose-1-phosphate aldolase-catalyzed aldol condensation of 2-azido-3-hydroxypropanal with dihydroxyacetone monophosphate (Scheme 13.17). The same method, applied to (2/ )-2-azidopropanal R)-V7 and to (25 )-2-azido-propanal (5 )-17, allows for the preparation of 2,5,6-trideoxy-2,5-imino-D-allitol 18 and 2,5,6-trideoxy-2,5-imino-L-talitol 19, respectively [22]. 

L-Allulose (LXI) was prepared by Steiger and Reichstein through the oxidative fermentation of allitol (LX) by the sorbose bacterium, Acetobacter xylinum. The product was isolated and purified by means of its crystalline diacetone derivative, of m. p. 57° and [a]o +99° in acetone. To the latter compound was assigned the l,2 3,4-diisopropyl-idene-L-allulofuranose structure LXII because it could be oxidized by alkaline permanganate to a crystalline uronic acid (LXIII) which, from its behavior, must have the carboxyl group in the 6- and not the 1-position. After removal of the isopropylidene groups from LXII, the free sugar, L-allulose (LXI), was obtained as a colorless sirup with — 3.3° in water. It is not fermented by yeast. 

Further examples on the use of 2,3 5,6-di-0-isopropyhdene-l-C-nitroso-D-mannofuranosyl chloride as a chiral dienophile for Diels-Alder reactions has been demonstrated by the preparation of l,5-imino-l,5,6-trideoxy-D-allitol, -D-gulitol and -D-glucitol. (See Vol. 29, p. 236, ref. 86 for other examples). 

A preparation of l,5-dideoxy-l,S-imino-D-allitol from A protected deoxynqjirimycin v ch involves a microbial redox reaction at C-3 has been described, and the glycosidase inhibitory properties of the product were determined together with those of other imino-alditols isolated from the leaves of Mens alba (see also ref 40 above). ... 

Anhydro-l-deoxy-l-nitro-D-altritol and D-allitol derivatives, prepared by cyclization of corresponding 1-deoxy-l-nitro-D-altritol or D-allitol derivatives in dimethyl sulphoxide, undergo equilibration on heating in aqueous solvents via acyclic nitroalkene intermediates whereas the altro isomer (18) predominated with 3,4-O-isopropylidene derivatives, the alio isomer (19) was preferred for the monocyclic derivative. ... 

Anhvdro-Alditols. - The synthesis of a whole range of 1,5- and 1,4-anhydro-alditols and their inhibitory effects against glycosidases have been reported. The preparation of 2,5-anhydro-3-deoxy-D-araWno-hexitol by hydrogenation of 2,5 3,4-dianhydro-D-allitol over Pearlman s catalyst has been described. The selective chlorination of pentitols to afford l,5-dichloro-l,5-dideoxy derivatives as well as mono- and di-chloro-l,4-anhydro derivatives has been reported. ... 

The preparation of l,5-anhydro-4,6-0-isopropylidene-D-allitol by way of an unexpected 6-endo ring opening of an epoxide has been described (Scheme 4). ... 

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