Turanose preparation

Alekhine had mentioned that turanose reacts with phenylhydrazine. Maquenne prepared the phenylosazone and described its precipitation from water in the flocculent or gel condition that is so very characteristic of the substance, but he did not report an analysis. A year after Ma-quenne s publication, Emil Fischer16 examined a small sample of amorphous turanose which had been sent by Dr. Konowaloff of Moscow. Its phenylosazone was prepared in good crystalline form by several recrystallizations from aqueous alcohol the analysis of these crystals proved conclusively the disaccharide formula for turanose which Alekhine had proposed from the analysis of amorphous substances. The writer had occasion recently to prepare turanose phenylosazone in considerable quantity its very characteristic properties and those of the derived phenylosotriazole are described on pages 27 and 28. 

The crystallization of turanose was first reported by Pacsu and the writer24 as follows In 1918 one of us (H.) found an abundant supply of the rare melezitose in a certain kind of honeydew honey and from it he prepared a small quantity of sirupy turanose in the hope of crystallizing it. Other samples of turanose sirup were prepared subsequently from this stock of melezitose by other workers in the same laboratory. Recently it was observed by D. H. Brauns that one of these sirups, the exact history of which is not now known, had crystallized after standing many years. By the use of these crystals to nucleate turanose sirups which we have lately prepared from melezitose, it has been possible to obtain a rapid crystallization of the sugar in abundant quantities. To this quotation the writer can now add the information, kindly supplied recently by Mr. C. F. Walton, Jr., that Mr. Walton prepared the other samples of turanose sirup. ... 

Turanose is readily purified by recrystallization from hot methyl alcohol, in which it is moderately, though slowly, soluble. In preparing the sugar, the first stage of the hydrolysis of melezitose by an acid solution is carried out under well controlled conditions, and is followed by the removal of the D-glucose from its mixture with turanose. This is usually accomplished by a selective fermentation with yeast, but an... 

Turanose phenylosotriazole, the configurational formula of which is XIV, was prepared from turanose phenylosazone. 

FIGURE 17.1 Mass spectrometric response ratio of turanose over n-octyl-glucopyranoside as a function of flow rates in nanospray. Turanose (10 mol/L) and w-octyl-glucopyr-anoside (10 mol/L) were prepared in neat solvent as a 10 1 (molar ratio) mixture. The curves represent the surface-to-volume ratio of initial droplets at different flow rates predicated using different theoretical models. [Reprinted from Schmidt et al. (2003) with permission.]... 

As shown in Table I (54), there is considerable difference in the ease of hydrolysis of oligosaccharides sucrose, with its fructofuranose ring, is particularly labile. The ease of hydrolysis of the sucrose linkage in comparison with that of the glycopyranosides makes it possible to hydrolyze preferentially the sucrose linkage in trisaccharides with the formation of a resistant disaccharide. Thus, turanose, a disaccharide, is prepared by the partial hydrolysis of the parent trisaccharide melezitose. 

Preparation 109). Melezitose is partially hydrolyzed by dilute sulfuric acid with the liberation of D-glucose and turanose. Then-glucose is removed by fermentation and the turanose crystallized directly. 

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