Glucitol 2,4-0-methylene

Diphosphitylation of 2,4-0-methylene-D-glucitol (8) with phosphorus trichloride in dioxane gave 1,3 5,6-bis- 0-(chlorophosphitc) 9 (99.5%). Its amination with diethyla-mine in benzene-diethyl ether afforded the corresponding bis-amidophosphites 10. Their reaction with sulfur afforded three P-diastereomers of cyclic thiophosphate 11 in 24.8, 4.8, and 19.5% yields (Scheme 4) [19],... 

The structure considered to be 2,3 4,5-di-O-methylene-D-glucitol could also be 2,4 3,5-di-0-methylene-D-glucitol. Haworth and Wiggins79 did not determine which of these structures the methyl L-gulonate derivative actually possesses. 

The synthesis of an alditol having a 4-membered (oxetane) ring was first reported by Ustyuzhanin and coworkers,50 who prepared 1,3-anhydro-5,6-di-0-methyl-2,4-0-methylene-D-glucitol by saponification of the 1-p-toluenesulfonate of the corresponding derivative of D-... 

With the aid of these rules, we have predicted the structures of the acetals which would be expected to result from the benzylidenation, ethylidenation and methylenation of all the tetritols, pentitols and hexi-tols. As will be seen from Table IV, the predicted structures agree very well with the accepted structures of the compounds. The rules explain, too, the syntheses of 3,5-benzylidene- and 3,5-methylene-gluco-[Pg.180]

Those parts of a polyol carbon chain not incorporated into an acetal ring, which appear as substituents in the ring, will be called residues. 2,4-0-Methylene-D-glucitol contains a /3C-ring, with the residues —CH2OH and —CHOH—CH2OH as substituents. 

Bicyclic trans diacetals with one axial residue will be considerably less stable than the acetals with equatorial residues this is shown by the absence of 3,5 4,6-diacetals of glucitol, 1,3 2,4-diacetals of mannitol and 2,4 3,5-diacetals of arabitol from the products of acetalation of the free glycitols. However, by suitable masking of hydroxyl groups, some trans diacetals with axial substituents should be obtainable. The most interesting will be 2,4 3,5-di-0-methylene-D-talitol (LIII), in which one terminal group is axial and the other equatorial (see p. 43). 

The investigation of poly-ester formation has been carried out using equi-molecular proportions of 1,3 2,4 5,6-tri-0-methylene-n-glucitol and adipic acid in excess trifluoroacetic anhydride, the latter serving as the solvent. After 3 hr. at room temperature, the volatile constituents were removed, and the reaction mixture was treated with an aqueous sodium bicarbonate... 

Studies of Trifluoroacetic Acid. Part XIV, Reaction of Acyl Trifluoroacetates with l 6-Di-0-benzoyl-2 4-3 5-di-0-methylene-D-glucitol, E. J. Bourne, J. Burdon, and J. C. Tatlow,/. Chem. Soc., 1274-1279 (1958). 

A novel diacetal of L-xi/lo-3-hexulose has been isolated in the course of studies on a general method for the synthesis of 3-hexuloses by oxidation of fully acetylated, hexitol monoacetals with chromium trioxide. Oxidation of l,2,5,6-tetra-0-acetyl-3,4-0-methylene-D-glucitol with chromium trioxide in acetic acid yielded principally l,2,5,6-tetra-0-acetyl-4-0-formyl-D-nbo-3-hexulose. The material remaining in the mother liquors was saponified with sodium methoxide in methanol and the product treated with acetone containing concentrated sulfuric acid a di-O-isopropylidene derivative, presumably l,2 3,4-di-0-isopropylidene-j8-L-xj/lo-3-hexulofuranose (116), was obtained. 

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