Sugar alcohols pentitols

Polarimetric analysis of sorbitol and mannitol in the presence of each other and of sugars is possible because of their enhanced optical rotation when molybdate complexes are formed and the higher rotation of the mannitol molybdate complex under conditions of low acidity (194). The concentration of a pure solution of sorbitol may be determined by means of the refractometer (195). Mass spectra of trimethylsilyl ethers of sugar alcohols provide unambiguous identification of tetritols, pentitols, and hexitols and permit determination of molecular weight (196). 

Paper electrophoresis (PE) Prior to PE separation of sugar alcohols into tetritols, pentitols, etc., separation by paper or thin-layer chromatography (TLC) is recommended. Basic lead acetate (0.178 mol 1 ) is the most useful electrolyte the run takes 3 h at 800 V. Other systems used are 0.05 mol 1 borate, run for 1.5h at 500V, or 0.2moll calcium acetate in 0.2 mol 1 acetic acid run for 2 h at 670 V. 

Cyclic polyalcohols (or cyclitols, according to the nomenclature of sugar alcohols) also have a very low affinity. The most important representative of this class of compounds is inositol, which exhibits a retention behavior comparable to that of pentitols. 

Sugar alcohols other than mannitol or those which have been found to be algal products do occur in lichens. The most common of these is arabitol which was found in 55 of 60 lichens examined (Lindberg et al., 1953). Arabitol is found in Xanthoria aureola and its role was suggested by photosynthetic studies on this lichen over 24 hours (Richardson and Smith, 1968a). Samples of lichen were placed on sodium [ C] bicarbonate solutions for 2 hours. The lichen was then removed, washed, and replaced in the lighten distilled water. After intervals of 4-48 hours samples were analyzed. A study of the soluble products (Fig. 2) showed that initially most of the radioactivity was in pentitol but as time progressed the amount of in mannitol rose. After 48 hours the amount of activity in the soluble fraction declined as the pulse of radioactivity was respired or converted to ethanol-insoluble compounds. A detailed study of the pentitol area showed that at first this... 

Lespieau, R., Synthesis of Hexitols and Pentitols from Unsaturated Poly-hydric Alcohols, II, 107-118 Levi, Irving, and Purves, Clifford B., The Structure and Configuration of Sucrose (oipta-D-Glucopyranosyl beta-D-Fructofuranoside), IV, 1-35 Liggett, R. W., and Deitz, Victor R., Color and Turbidity of Sugar Products, IX, 247-284... 

Although the polyhydric alcohols derived from sugars have been the subject of numerous investigations over many years, the inner ethers or anhydrides of these substances have been for the most part neglected, despite the fact that many of them were isolated and some description of their properties recorded before the advent of the twentieth century. In recent years, however, the anhydrides of polyhydric alcohols derived from sugars have received marked attention in several countries. Some indeed have achieved importance in chemical industry. Most interest has been centered on the anhydrides of pentitols and hexitols and this article will be restricted to a discussion of the chemistry of these substances. 

Sugar alcohote polyhydric alcohols, which occur widely as metabolic reduction products of monosaccharides. Ttey are named by repladng the -ose ending of the parent monosaodiaiide by -itol . According to the number of carbon atoms they are classified as pentitols, hexitols, etc. S.a. show only low optical activity, are not fermented by yeasts, and do... 

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