Carbohydrate derivatives Sorbitol

Other sweeteners that have expanded the food options for diabetics are known as sugar alcohols. These are carbohydrate derivatives, such as sorbitol, in which the carbon-oxygen double bond of the aldehyde or ketone has been converted to an alcohol ... 

Isosorbide, a renewable and commercially available carbohydrate derived from D-sorbitol served as a chiral substituent in the p-amino alcohol ligands 51 and 52 which were evaluated for the metal-catalysed enantioselective reduction of aromatic ketones [70]. The best result for [Ru(p-cymene)Cl2]2-catalysed reduction of acetophenone with i-PrOH/t-BuOK was obtained in the presence of the ligand 51 (94 % conversion and 91 % ee for (R)-l-phenylethanol), while a slightly different position of a chiral centre on the hydroxyethylamino moiety as in the ligand 52 led to a drastic drop of activity and enantioselectivity (28 % conversion, and 47 % ee... 

From carbohydrates, several diphosphines have been derived and used as ligands in hydroformy-lation reactions (Section D.l. 5.8.). a,a -TREDFP (a,a -40) is prepared from commercially available a, a -trehalose (39) by the reaction sequence outlined42,43 similarly, the / ,/f-anomer is obtained from / ,/ -trehalose44. L-Iditol is commercially available but expensive, but may be prepared by catalytic reduction of L-sorbose and separation from the isomeric L-sorbitol by fractionated crystallization of the hexaacetate45. Conversion to the diphosphine 42 involves a further fractional crystallization for the separation of isomeric ditosylates46. The reactions for the synthesis of the precursors employ techniques described in Section 4.4. for the derivatization of carbohydrates. 

The basic petrochemical feedstocks are ethylene and benzene which are converted to the surfactant intermediates ethylene oxide, linear alkyl benzene (LAB), and detergent alcohols. Oleochemical or natural surfactants are commonly derived from plant oils (coconut and pahn oils), from plant carbohydrates such as sorbitol, sucrose, and glucose or from animal fats such as tallow. 

The innermost zone covers chemicals for which no petrochemical route exists, and therein lies a great opportunity to produce them from carbohydrate feedstocks (in the case that a market for them is present or arises) gluconic [91,92] and glucaric acids [17], furyl glycolic acid [87], furandicarboxylic acid [85], and fermentation-derived malic, citric, succinic, and itaconic acids [17]. Besides these, the sugar alcohols xylitol [78] and sorbitol [81, 93-95], as well as isosorbide [82, 96, 97], HMF [80,98], and furfural [44,99] are also present, along with tetroses and their derivatives obtained by dehydration [100]. For these molecules, it is virtually certain that no petrochemical-based production will ever be developed. Note that levulinic acid [67, 101-103] is at the border of this zone. 

D-Fructose./nritsugat levulose a ketohexose, M, 180.16, m.p. 103-105 °C (d.), [alg -135°->-92° (c = 2, water). F. tastes sweeter than any other carbohydrate and is fermentable by yeast. It crystallizes as the P-pyranose, but is present in compounds as the furanose (see Carbohydrates). Chemical reduction yields a 1 1 ratio of D-sorbitol and D-mannitol. Its me-tabolically important derivatives are fructose 1,6-bis-phosphate and the I-phosphate. 

Chiral ferroceneboronic acid derivatives have been synthesized by Ori and tested for chiral electrochemical detection of monosaccharides. The best discrimination was observed for L-sorbitol and L-iditol at pH 7.0 in 0.1 mol dm phosphate buffer solution. Moore and Wayner have explored the redox switching of carbohydrate binding with commercial ferrocene boronic acid. From their detailed investigations, they have determined that binding constants of saccharides with the ferrocenium form are about 2 orders of magnitude greater than those for the ferrocene form. The increased stability is ascribed to the lower pKe of the ferrocenium (5.8) than ferrocene (10.8) boronic acid. 

Borate buffers should not be used in the presence of polyols, including carbohydrates and their derivatives, with which they may form chelate compounds they react in this way with many respiratory intermediates. Use of borate buffers in gel electrophoresis of proteins can result in spreading of the zones if fructose, ribose, sorbitol, catechol or other appropriate polyols are present to form borate complexes (Lerch and Stegemann, 1969). The increased solubility of adrenalin in borate buffers is due to complex formation as is also the improved separation of sugar phosphates chromatographically in the presence of borate buffers. Likewise, complexation of carbohydrates in german-ate or borate buffers is the basis of a suggested method for... 

Description. The common aspect among the surfactants grouped in this class and the sorbitan esters and alkyl carbohydrates esters classes is that they all derive from the condensation reaction of a polyhydroxyl compound (glycol, glycerol, sorbitol, sucrose, etc.) with a fatty acid. Some of them can be directly extracted from natural sources. 

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