Hexitols 1,4-anhydro

The Action of Alkali on Methyl 2 3-Anhydro-a-D-allopyranoside and l 5-Anhydro-2-deoxy-3-0-toluene-p-sulphonyl-D-arabino-hexitol," A. B. Foster, M. Stacey, and S. V. Vardheim, Acta Chem. Scand., 12(1958) 1819-1824. 

On treatment with concentrated halogen acids, certain hexitols yield 1,6-dideoxy-l,6-dihalo compounds. The structure of the compound so obtained from galactitol, first reported by Bouchardat,404 was later verified by synthesis.405 Allitol is transformed406 into 1,4-anhydro-6-chloro-6-deoxy-DL-allitol and l,4-anhydro-5,6-dichloro-5,6-dideoxy-DL-talitol on treatment with fuming hydrochloric acid at 100°. 

Crystalline 1,4-anhydro-D-sorbitol is of much more recent origin than 1,4-anhydro-D-mannitol, inasmuch as its preparation was first recorded in 1946.10 It was obtained by the restricted dehydration of D-sorbitol and has been given the trivial name arlitan. Two groups of workers simultaneously effected proof of its constitution. Hockett and coworkers11 treated the anhydride with lead tetraacetate and since its rate of oxidation coincided with that of ethyl D-galactofuranoside and since one molecular proportion of formaldehyde was formed, the authors concluded that the ring must involve Cl and C4 of a hexitol chain. Assuming that no other carbon atoms are involved, sorbitan is either 1,4-anhydro-D-sorbitol or 1,4-anhydro-D-dulcitol (Walden inversion at C4 of the sorbitol molecule). They therefore synthesized 3,6-anhydro-D-dulcitol (enantio-morphous with 1,4-anhydro-L-dulcitol) but found it to be different from arlitan. 

The chemical reactions of the hexitols are similar to those of the simple sugars, uncomplicated by the presence of a carbonyl group. The hexitols exhibit a higher order of stability to acid, alkali and heat. They are readily converted to stable anhydro products. These anhydrides are known as hexitans when one mole of water is removed and hexides when two moles are removed. 

Anhydro-l,3,6-trideoxy-L-rtbo-hexitol-l-yl)-trimethyl-ammonium chloride [L-(+)-Muscarine chloride] 2,5-Anhydro-/3-D-arabinofuranose 179-80... 

Figure 1. Variation in molecular rotation with increasing concentrations of dimethyl sulfoxide in 1,2-dichloroethane (1) l,5-anhydro-2,3-dideoxy-6-0-methyl-D-erythro-hexitol (8) (2) l,5-anhydro-2,3-dideoxy-D-erythro-hexitol (5) (3) ln,2s-hydroxy-methylcyclohexanol (4).

The low boiling component was isolated by fractional distillation at 80°-85°C (13 mm pressure). The material was impure -2 acetoxy-methyltetrahydropyran (I). The isolation and characterization of the two other components are described in relation to the preparation of 7 and l,5-anhydro-2-deoxy-D-it/xo-hexitol. 

The above compound, l,5-anhydro-2,3,4-trideoxy-6-0-triphenyl-methyl-D-gZt/cero-hexitol (4.0 grams) was dissolved in 75 ml of chloroform. Dry hydrogen bromide was bubbled through the solution kept at 0°C until TLC examination showed all the starting material had disappeared. The solution was concentrated at 30 °C and 13 mm pressure to a semi-solid mass. The pressure was then reduced to 0.08 mm, and the... 

Anhydro-2,3 -dideoxy-4-0-methyl-D-ery l>ro-hexitol (10). Tri-phenylmethylation of 4 (18.0 grams) as described above for 48 hours followed by isolation of the product by the usual method gave 20 grams of a crystalline product that was a 1 1 complex of the desired compound and pyridine (mp 60o-100oC, [ ]D25 — 33° (c, 0.5 in chloroform)). 

Another example is the formation of an anhydro-l,6-di-0-benzoyl-di-0-tosyl-D-hexitol (along with the expected 2,3,4,5-tetra-O-tosyl derivative)... 

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