D-Lyxose diacetamide

D-Lyxose diacetamide. Ammonia-silver oxide.y Ten grams of pentaaoetyl-n-galactononitrile was dissolved in 30 ml. of ethanol, and a solution of silver oxide (from 5 g. of silver nitrate) in 50 ml. of 30 % ammonia added. After two days at room temperature, the precipitated silver cyanide was removed by filtration and the solution evaporated in vacuo at 40° imtil all ammonia was eliminated. The residue was diluted with water and the soluble silver eliminated by treatment with hydrogen sulfide and filtration. The filtrate was treated with decolorizing carbon, filtered and evaporated to dryness. When the residue crystallized, it was suspended in warm ethanol and filtered yield, 2.5 g. (40%). After recrystallization from 60% ethanol, the product had a melting point of 230-231°. 

D-Fucose (Rhodeose). Voto6ek obtained tetraacetyl-D-fucononitrile in 25% yield by treating D-fucose oxime with sodium acetate-acetic anhydride. The nitrile, degraded with ammonia and silver oxide, yielded 5-desoxy-D-lyxose diacetamide in 40% yield. The diacetamide compound was hydrolyzed with 5% hydrochloric acid and the 5-desoxy-D-lyxose was obtained in solution and characterized as the p-bromo-phenylosazone. Hydrolysis of the diacetamide compound with 6 N sulfuric acid was realized by Voto6ek and Valentin and the 5-desoxy-D-lyxose was isolated as a sirup. 

By employing aqua ammonia, the yield of D-lyxose diacetamide from the nitrile was improved to 72%. Degradation of the nitrile with sodium methoxide yielded 30% of D-lyxose, isolated as the p-bromo-phenylhydrazone. Treatment with silver carbonate subsequent to hydrolysis of the acetyl groups resulted in a 22% yield. 

Pentapropionyl-D-galactononitrile has been prepared in 52 % yield by Gim6nez from the oxime and pyridine-acetic anhydride. Degradation with ammonia-silver oxide produced D-lyxose diacetamide in 30% yield. 

D-Galactose. Wohl and List prepared pentaacetyl-n-galactononitrile from the oxime in 40% yield. Degradation with ammonia-silver oxide gave 40% of n-lyxose diacetamide. Hydrolysis of the diacetamide with... 

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