DL-Ribitol

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,... 

Acid hydrolysis of cytidine ribitol pyrophosphate led to a series of products, depending on the conditions of hydrolysis. L-Ribitol 1-phosphate (n-ribitol 5-phosphate), isomeric ribitol phosphates formed by acid-catalyzed migration of the phosphate group from the terminal position, and 1,4-anhydro-DL-ribitol were isolated. 

An interesting counterpart of the above reaction has been found by Baddiley and associates in the hydrolysis of L-ribitol 1-phosphate (which is the same as n-ribitol 5-phosphate) which, under acid conditions N hydrochloric acid), results in the formation of 1,4-anhydro-DL-ribitol. 

P. Chautemps " obtained diepoxides from 1,4-pentadien-3-one (87) as a mixture of DL and meso compounds (88 89 as 13 7). Reduction of the carbonyl group in DL-diepoxide (88) followed by alkaline hydrolysis gave DL-arabinitol. Analogously, from meso diepoxide 89 a mixture of DL-ribitol and DL-xylitol was obtained. 

Anhydro-derivatives of DL-ribitol and DL-arabinitoland 2,5 3,4-dianhydro-l-halo-l-deoxypentitols,have been prepared froir... 

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. 

Pentadienone (divinyl ketone) was epoxidized55 by means of hydrogen peroxide in alkaline solution, to give a mixture of DL- and me.so-l,2 4,5-dianhydro-3-pentanones in the ratio of 13 7. Reduction of the ketone group in the DL-diepoxide with sodium horohvdride, followed by alkaline hydrolysis in dimethyl sulfoxide, was fully stereo-specific, and afforded DL-arabinitol. The same reaction-sequence performed on the meso-diepoxide led to a mixture of ribitol and xylitol. 

Deoxy-2,4 3,5-di- O -methylene-D-Jtylitol, D-385 l-Deoxy-2,4 3,5-di-0-methyIene-L-xylitol, D-385 l-Deoxy-2,4 3,5-di-0-methyIene-DL-xylitoI, D-385 l-Deoxyiditol D-form, D-237 5-Deoxy-2,3-0-isopropylidene-i>ribitol, D-356 l-Deoxy-2,4-0-methylene-3,5-di-0-tosyI-D-xylitol, D-385 1 -Deoxy-2,4-O -methylene-5-O-tosyI-r>-xylitol, D-385 l-Deoxy-2,4-methylene-D-xylitol, D-385 1-Deoxyribitol D-form, D-356 1-Deoxyribitol D-form, D-356... 

Tetra-0-acetyl-5-deoxy-DL-arabinitol, D-40 Tetra-O-acetyl-l-deoxy-D-ribitol, D-356... 

A monograph (in Russian) has appeared on catalytic hydrogenation and hydro-genolysis of carbohydrates. The influence of the composition of nickel-alumina and other catalysts on the hydrogenolysis of D-glucose has been investigated. DL-Arabinitol, ribitol, and xylitol have been synthesized from 3-hydroxypenta-1,4-diene (divinyl carbinol) by the routes outlined in Scheme 80. ... 

DL-Arabitol, m.p. 105° pentaacetate, m.p. 95° is not found in nature and can be prepared from an equimolar mixture of the enantiomorphs. It has been obtained synthetically along with ribitol by Lespieau ( 0). The synthetic approach used by Lespieau is of general application and is equivalent to a total synthesis. The steps taken are as follows ... 

Synthetic ribitol has been prepared by the reduction of L-ribose with sodium amalgam (28), Oddly enough, whereas L-ribose is a synthetic pentose, ribitol does not appear to have been prepared from the naturally occurring D-ribose. Lespieau (20, 29) and Raphael (21) have each obtained ribitol along with DL-arabitol in their syntheses from noncarbohydrate precursors, mentioned previously. 

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