Acetals and Ketals of the Tetritols

Condensations of erythritol with benzaldehyde,78,78 o-, wi-andp-chloro-benzaldehyde,18 p-methylbenzaldehyde,18 p-methoxybenzaldehyde,18 o-, m- and p-nitrobenzaldehyde,18,87 3-nitro-4-chlorobenzaldehyde,18 acetaldehyde,74 chloroacetaldehyde,74 acetone,1718 formaldehyde,78 and val-eraldehyde76 have been reported, but in no case has the structure of the product been determined. The physical constants of these acetals and ketals are recorded in Table VII. The photo-sensitivity of o-nitrobenzyl-idene-erythritols has been discussed on page 149. 

The dibenzylidene derivatives of d-, l- and D,L-threitol were prepared by Maquenne and Bertrand,78 dry hydrogen chloride being used as the catalyst. With the aid of these acetals, and also of those derived from valeraldehyde, these workers were able to differentiate between the active and inactive erythritols. Although the finer structures of these compounds are, as yet, unknown, the dibenzylidene derivatives 

3-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. 

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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... 

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

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