Xylitol, 1,5-anhydro

In a detailed study of the deamination of the four 1-amino-1-deoxy-D-pentitols (109-112), the products were analyzed by g.l.c. It was found that each aminodeoxypentitol gives three products in differing ratios.202 In addition to the pentitol and the corresponding 1,4-anhydropentitol, there is formed a second 1,4-anhydropentitol. The latter was found to be formed by ring closure between the 5-hydroxyl group and C-2, with inversion at C-2. For example, 1-amino-1-deoxy-D-lyxitol gives 1,4-anhydro-D-lyxitol, 2,5-anhydro-D-xylitol (= 1,4-anhydro-L-xylitol), and D-lyxitol. Because the second 1,4-... 

Ditosyl 2,5-Anhydro-3,4-di-0-tosyl-D-xylitol. 1,4-Anhydro-2,3-di-O-tosyl-L-xylitol... 

The synthesis of all positional isomers of partially methylated-acetylated or methylated-benzoylated derivatives of 1,4-anhydro-D-xylitol, 1,4-anhydro-L-fucitol, 1,4-anhydro-D-ribitol, 1,5-anhydro-D-mannitol, 1,5-anhydro-D-gJu-citol, and IjS-anhydro-D-galactitoP" have been described. The compounds should be useful as standards for determining the primary structure of polysaccharides after reductive cleavage. 

C10H2oN05P 2,5-Anhydro-4-0-methyl-D-xylitol 1,3-phosphate diethylamide (EAPMXY10)57... 

C6H10N2O4 (lS,2R,3R,4R)-l,4-Anhydro-2-deoxy-l,2-0-ureylene-D-xylitol DURXYF 43 370... 

Cleavage of the dithioacetal groups from the products, followed by reduction of the resultant carbonyl derivatives (46, 49, 52) with sodium borohydride leads,68 with the three compounds (45, 48, and 51), to 1,4-anhydro-L-ribitol (2,5-anhydro-D-ribitol) (47), 1,4-anhydro-L-xylitol (2,5-anhydro-D-xylitol) (50), and 1,4-anhydro-D-arabinitol (2,5-anhydro-D-lyxitol) (53), identified by comparison with their enantiomorphs, 1,4-anhydro-D-ribitol,69 1,4-anhydro-D-xylitol,70 and 1,4-anhydro-L-arabinitol. 71... 

In contrast to ribitol and xylitol (which form a dl mixture on anhydride formation because of their molecular symmetry), D-arabinitol may, in principle, on heating with acid, give two different anhydrides, namely, a 1,4-anhydroarabinitol ora 2,5-anhydroarabinitol (1,4-anhydro-lyxitol), as the following reaction sequence illustrates. 

On heating pentitols with acid under more drastic conditions, derivatives of 1,4-anhydrides may be produced. Thus, on treating molten xylitol with dry hydrogen chloride at 100°, or in concentrated hydrochloric acid at 106-108°, a moderate yield of syrupy 1,4-anhydro-5-chloro-5-deoxy-DL-xylitol was obtained.16... 

The enantiomorph, also a syrup, was synthesized from 3,6-anhydro-4,5-O-isopropylidene-D-mannitol18 by periodate oxidation to the corresponding D-arabinose derivative, followed by reduction in the presence of Raney nickel.17 2,5-Anhydro-D-xylitol, 2,5-anhydro-D-ribitol, and 2,5-anhydro-D-lyxitol (1,4-anhydro-D-arabinitol)19,20 were... 

The formation of oxetane (1,3-anhydro) rings has received but little attention. l,3-Anhydro-2,4-0-methylene-DL-xylitol was obtained22 from 2,4-O-methylene-l-O-p-tolylsulfonyl-DL-xylitol. The 1,3-ring was established by elimination of the possibility of other products, through test reactions and formation of derivatives.22... 

The second dianhydro-xylitol was obtained23 by methylenation of 1,4-anhydro-DL-xylitol, with paraformaldehyde and concentrated hydrochloric acid, to give the 3,5-methylene acetal this was methylated to the 2-methyl ether, which was hydrolyzed, and the product mono-p-toluenesulfonylated to the 5-p-toluenesulfonic ester. On treatment with aqueous sodium hydroxide at 40-50°, the last gave syrupy l,4 3,5-dianhydro-2-0-methyl-DL-xylitol (17, D form). 

The infrared spectra of l,4-anhydro-3,5-0-methylene- and -2-0-methyl-DL-xylitol have been studied.60 The 2-methyl ether was obtained by converting l,4-anhydro-3,5-0-methylene-DL-xylitol into its monomethyl ether, and then hydrolyzing off the methylene group. A methyl ether prepared from the known l,4-anhydro-3,5-0-isopro-pylidene-2-O-methyl-DL-xylitol proved to be identical with this compound, thus establishing at the same time that the methylene group in the known acetal is attached to 0-3 and 0-5 of 1,4-anhydro-DL-xylitol. The methylene group, having a 1,3-dioxolane structure, was characterized by an absorption band at about 2800 cm 1. 

Danilov and coworkers79 treated l,4 3,5-dianhydro-DL-xylitol with a number of primary and secondary amines. The 3,5-anhydro ring was opened, to give the corresponding 5-amino-5-deoxy compounds. 

Although these anhydropentitols lack the cis-trans triple-ester arrangement, the following respective intermediates from 1,4-anhydro-tri-O-benzoyl-D-ribitol and tri-0-acetyl-l,4-anhydro-D-xylitol were proposed, in order to account for the epimerizations that occur. 

For 1,4-anhydro-xylitol, ring opening was postulated to occur as follows ... 

O-methylene-DL-arabinitol l,4-Anhydro-2-anilino-2-deoxy- xylitol 145... 

The competitive inhibition of aldolase by a number of structural analogs of D-ftuctose 1,6-diphosphate has been investigated.120 Among these analogs were 1,4-anhydro-DL-ribitol 5-phosphate, 1,4-anhydro-DL-xylitol 5-phosphate, 1,4-anhydro-D-arabinitol 5-phosphate, 2,5-anhydro-D-mannitol 1,6-diphosphate, and 2,5-anhydro-D-glucitol 1,6-diphosphate. Their respective, enzyme-inhibitor,... 

Cyclization between a 1-amino group and C-4 of an anhydropenti-tol has been achieved 2,5-anhydro-l-azido-l-deoxy-3,4-di-0-p-toIyl-sulfonyl-D-xylitol (48) was hydrogenated to the 1-amino compound and then this was N-p-toluenesulfonylated, giving 49 the product was cyclized by use of sodium methoxide to38,39 the bicyclic compound (50). 

An even more interesting reaction, with potentialities which should be further explored, is that which occurs when l,3-anhydro-2,4-0-methylene-D,L-xylitol is treated180 with p-toluenesulfonyl chloride in pyridine (during 3 days at room temperature and then 8 hours at 70°). The expected 5-O-tosyl derivative is accompanied by a monochloro-monodeoxy-2,4-0-methylene-di-0-tosyl-D,L-xylitol formed by opening of the anhydro-ring. 

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. 

Peracetylated 1,5-anhydro-D-glucitol (41), -D-mannitol (42), -D-galactitol (43), -D-xylitol (44), -D-ribitol (65), and 2,3,5-tri-0-acetyl-1,4-anhydro-D-ribitol (66) were prepared in high yield from the corresponding glycosyl bromides on treatment with titanocene boiohydride (CpzTiBHO.193 The reaction also proceeded with... 

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