Other Polyfructosans

A large number of polyfructosans that have been reported from time to time by different authors have been investigated by Schlubach and his associates. In order to obtain polysaccharides of constant optical rotation, 100 to 300 precipitations from aqueous solution by the addition of alcohol were necessary. Fifty to 150 precipitations from chloroform solution with petroleum ether were required for purification of the acetate derivatives. These were methylated according to the procedure of Haworth and Streight, and upon hydrolysis partially methylated fructoses were obtained. 

It is believed by Schlubach and Sinh that the polyfructosans are, as a rule, made up of D-fructose residues joined in a ring. According to these authors, when the methyl derivatives of the polysaccharides are hydrolyzed, the amounts of dimethyl- and tetramethyl-D-fructose formed 

The polysaccharide was acetylated with acetic anhydride in the presence of pyridine. Purification of the acetate consisted in precipitation of a 10% boiling benzene solution with petroleum ether. One hundred and fifty such precipitations were necessary before a constantrotating product resulted = — 20.1° (c = 1.0, chloroform). 

Cryoscopic molecular weight determinations in benzene solution gave an average value of 3918. 

The acetate was dissolved in acetone and converted to the methyl derivative by the use of dimethyl sulfate and sodium hydroxide. After three methylations, a product containing 45.6% OCHa was obtained. Hydrolysis yielded dimethyl-, trimethyl-, and tetramethyl-D-fructose in the ratios (calculated as D-fructose) of 1 8 1. The trimethyl-D-fructose 

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