The Acetylated Carbohydrate C-Nitroolefins

Experimental Details,64—Three grams of 1-nitro-l-desoxy-D-mannitol was acetylated on the steam bath for one-half hour with 20 cc. of acetic anhydride containing one drop of sulfuric acid to give 5.26 g. (88%) of the crystalline pentaacetate. After recrystallization from a mixture of ether and petroleum ether, the product melted at 88-89° and showed [a] 37.8° in absolute chloroform, c 7.3. Neither pyridine nor sodium acetate was found to be satisfactory for catalysis of the acetylation, both yielding dark colored sirups. 

One gram of 1-nitro-l-desoxy-D-mannitol pentaacetate in 20 cc. of dry benzene was refluxed for two and one-half hours with 1 g. of sodium bicarbonate. The mixture was cooled, filtered and concentrated to dryness. The resulting residue, on recrystallization from a mixture of ether and petroleum ether, yielded 0.74 g. (86%) of the acetylated nitroolefin. D-ara6o-Tetraacetoxy-l-nitrohexene-l melts at 115-116° and shows [a] 32.4° in absolute chloroform, c 5.2. 

In similar fashion, 6-nitro-6-desoxysorbitol gives 87 percent of the acetylated nitroolefin, L-zyfo-tetraacetoxy-l-nitrohexene-l, without purification of the intermediate, sirupy nitroalcohol pentaacetate.54 1-Nitro-1-desoxy-D-arabitol tetraacetate30 gives, in the Schmidt and Rutz reaction, 81 percent of D-en/fftro-triacetoxy-l-nitropentene-1 1-nitro-l-desoxy-D-manno-D-graZa-heptitol hexaacetate42 similarly gives 90 percent of D-marmo-pentaacetoxy-l-nitroheptene-1. 

Acetylated nitroolefins have been prepared in similar fashion from D-erythrose,80 D-arabinose, D-ribose and D-glucose. The ease with which the acetylated nitroolefins usually crystallize is exemplified by the experience with D-glucose. Here, the product, D- lwco-pentaacetoxy-1-nitroheptene-1, was obtained in the crystalline state from a sirupy mixture containing approximately twenty times the nitroolefin s weight of other acetylated carbohydrate material, formed from the original 

D-glucose, the bulk of the latter having failed to condense with the nitromethane. 

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The selective hydrogenation of the olefinic double bond in the acetylated carbohydrate C-nitroolefins, using palladium black as catalyst, depends to a marked degree on the solvent employed. In absolute ethanol a sharp decrease in the rate of hydrogen absorption usually occurs when the double bond has been saturated. This decrease in rate is not sharply defined in 95 percent ethanol and is not detectable when absolute ethyl acetate is employed as the hydrogenation solvent. 

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