PENTAACETYL-d-GLUCONONITRILE

In his first paper Wohl reported the conversion of D-glucose oxime (I) into pentaacetyl-D-glucononitrile (II). 

In the case of the oximes of the aldose sugars, the situation is more complicated because of the possibility of both open-chain and cyclic structures. That aldose oximes can react in the open-chain form follows from the formation of the nitriles and from the isolation of acylated open-chain aldose oximes as secondary products in preparation of nitriles. For example, Wolfrom and Thompson, by the action of sodium acetate-acetic anhydride on n-glucose oxime, not only obtained pentaacetyl-D-glucononitrile, in 40% yield, but also isolated a small amount of hexaacetyl-oWeAydo-D-glucose oxime (V) identical with that prepared by mild acetylation of pentaacetyl-aWe%do-D-glucose oxime (IV) whose structure was assured by its formation from pentaacetyl-aldehydo-D-glucoae (III). 

Wohl isolated a hexaacetyl-D-glucose oxime from the mother liquor obtained during the preparation of pentaacetyl-D-glucononitrile. The same acetylated oxime was prepared by Behrend. Wolfrom and Thompson studied it further, and showed conclusively that it possessed a ring structure XI, for it could not be transformed into a nitrile. Because of its low specific rotation, it was assigned to the jS-d series. 

The acetylated nitriles can also be obtained by dehydration of the corresponding amides. Phosphorus oxychloride is employed as the dehydrating agent. In this way Zempl n and Kiss prepared hexa-acetyl-D-gluco-D-g w/o-heptononitrile, and Ladenburg, Tishler, Wellman and Babson, tetraacetyl-n-ribononitrile, tetraacetyl-n-arabononitrile and pentaacetyl-D-glucononitrile. 

The work which Wohl reported in his earliest paper on sugar degradation had been planned with the expectation that the nitriles of the aldonic acids would react as cyanohydrins. When he carried out his first degradation with pentaacetyl-D-glucononitrile (XXIX) he used ammonia... 

Removal of the acetyl and nitrile groups by acid hydrolysis was also achieved by Wohl, who isolated a pentosazone from the products from heating pentaacetyl-D-glucononitrile with 2 N hydrochloric acid. Fischer also isolated what is now known to have been a 5-desoxy-L-arabinosazone from the products obtained by treatment of tetraacetyl-L-rhamnononitrile with 5% hydrochloric acid. At the same time partial transformation of the nitrile into the aldonic acid takes place as shown by Maquenne, who obtained D-xylonic acid by treating tetraacetyl-D-xylononitrile with concentrated hydrochloric acid. 

Zempl6n and Kiss, in the case of pentaacetyl-D-glucononitrile, removed the acetyl groups by heating the compound with sulfuric acid in ethanol, a procedure that left the nitrile almost intact. This group was subsequently eliminated with silver carbonate and D-arabinose was isolated as the diphenylhydrazone. This procedure was applied to other nitriles by Deulofeu and coworkers. ... 

D-Glucose. WohP obtained pentaacetyl-n-glucononitrile in 40% yield by the action of sodium acetate-acetic anhydride. The nitrile when treated with ammonia-silver oxide gave a 47 % yield of n-arabinose diacetamide. Hydrolysis of the diacetamide derivative with 6 N sulfuric acid produced crystalline n-arabinose in 50-60 % yield. The process was improved by Neuberg and Wohlgemuth, who obtained n-arabinose in an over-all yield of 34.7 % of the n-glucose employed. 

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