Tetritols acetals

Barker, S. A., and Bourne, E. J., Acetals and Ketals of the Tetritols, Pentitols and Hexitols, VII, 137-207 Barrett, Elliott P., Trends in the Development of Granular Adsorbents for Sugar Refining, VI, 205-230 Barry, C. P., and Honeyman, John, Fructose and its Derivatives, VII, 53-98... 

Tetritols, especially erythritol, have been included in model studies on the separation of alditol acetates (see, for example, Refs. 217 and 417), and a commercial analysis of glycerol as its acetate has been proposed.597... 

In the course of studies on the reactivity30 of fluoro carbohydrates, the 3,4-isopropylidene acetals of 2-deoxy-2-fluorotetritols were obtained. These react with the Pnrdie reagents under mild conditions, to give the corresponding O-methyl derivatives. More-vigorous reaction-conditions cause expulsion of the fluorine atom, leading to 3,4-0-isopropylidene-l,2-di-0-methyl-DL-tetritols. Mild oxidation of 2-de oxy-2-fluoro-3,4-0 -isopropyl ide ne-DL-ery thritol with barium... 

The acetals and ketals which will be considered are those formed from the tetritols, pentitols, and hexitols, on the one hand, and the simpler carbonyl compounds (e.g. acetone and benzaldehyde), on the other. 

The Oxidation of Acetals and Ketals of the Tetritols with Glycol-splitting Reagents... 

Benzylidene-D-threitol (VII) was prepared by Haskins, Hann and Hudson79 by hydrogenation of 2,3-benzylidene-D-threose, a product of the periodate oxidation of 2,3-benzylidene-D-arabitol. The tetritol was proved to be D-threitol, rather than erythritol, by the fact that hydrolysis of VII and subsequent treatment with benzaldehyde afforded the known dibenzylidene-D-threitol. The acetal group was allocated to the 2,3-position on the basis of independent evidence concerning the structure of the parent benzylidene-D-arabitol (see page 152). For the physical constants of acetals of threitol see Table VIII. 

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]

A difference in the behavior of methanesulfonic and p-toluenesul-fonic esters of 1,3-0-benzylidene-tetritols on reduction with lithium aluminum hydride in tetrahydrofuran has been described by Foster and coworkers 1,3-0 -benzylidene -2,4 - di - O - p - tolylsulfonyl - L -erythritol and -L-threitol gave the corresponding 4-deoxytetritol acetals, whereas l,3-0-benzylidene-2,4-di-0-(methylsulfonyl)-L-threitol was simply demethanesulfonylated to 1,3-O-benzylidene-L-threitol. 

Treatment of 2-carboxy-3-methoxycarbonyl-5-(D-arahmo-tetritol-l-yl)-pyrrole (700) with acetic anhydride caused bimolecular cyclocondensation with simultaneous O-acetylation to yield 701 (74MI8) (Scheme 179). 

---