Glucose acylation

Another microbial polysaccharide-based emulsifier is Hposan, produced by the yeast Candida lipolytica when grown on hydrocarbons (223). Liposan is apparentiy induced by certain water-immiscible hydrocarbons. It is composed of approximately 83% polysaccharide and 17% protein (224). The polysaccharide portion consists of D-glucose, D-galactose, 2-amino-2-deoxy-D-galactose, and D-galacturonic acid. The presence of fatty acyl groups has not been demonstrated the protein portion may confer some hydrophobic properties on the complex. 

One particular feature of ionic liquids lies in their solvation properties, not only for hydrophobic compounds but also for hydrophilic compounds such as carbohydrates. Park and Kazlauskas reported the regioselective acylation of glucose in 99 % yield and with 93 % selectivity in [MOEMIM][BF4] (MOE = CH3OCH2CH2), values much higher than those obtained in the organic solvents commonly used for this purpose (Entry 18) [22] (Scheme 8.3-4). 

Gene activated Lipoprotein lipase fatty acid transporter protein adipocyte fatty acid binding protein acyl-CoA synthetase malic enzyme GLUT-4 glucose transporter phosphoenolpyruvate carboxykinase... 

The Merck compound MK-0608 is a 2 -C-Me-7-deaza-adenosine analog, which has recently been reported to show a 5.7 log drop in viral load in HCV-infected chimpanzees after dosing QD at 2mg/kg (Olsen 2006). An efQcient and practical process for preparing kilogram quantities has been described (Bio et al. 2004). The 12-step synthesis provides an impressive 35% overall yield and starts from the inexpensive diacetone-D-glucose. The synthesis features a novel acyl migration in route to prepare the key crystalline furanose diol intermediate (Fig. 5). The conditions... 

Three types of carbohydrate sample have been reported to give data above mass 4000, namely, permethylated polysaccharides, permethylated glycosphingolipids, and naturally acylated forms of a mycobacterial O-methyl-D-glucose polysaccharide. All are hydrophobic, and desorption is probably facilitated by their inability to form strongly hydrogen-bonded aggregates, either with themselves or with the matrix. 

Chemical variety in the acylsugars known from the family is based upon the capacity of glucose to accommodate up to five acylating acids, while sucrose can accommodate up to six. Detailed chemical information on these compounds from various members of the family can be found in papers by King et al. (1988,1990) and Matsuzaki et al. (1989). In the case of compounds from L. pennellii, the acylating acids... 

Since anthocyaifins acylated with aliphatic acids are sensitive to acids, as verified, for example, in fruits of R suberosa when extracted with methanol containing 0.1% HCl," their occurrence in foods may be underestimated. Malonyl acylation in glucose at its position 6 was found in anthocyanins from blood... 

However, evidence for the hnkage position of this acyl group was only reported for blood oranges at position 6 of the 3-glucose moiety. Anthocyanins acylated with malyl acid were detected only in blackberries of an unknown cultivar. "... 

Ganske and co-workers reported that lipase-catalyzed acylation of a glucose derivative proceeded smoothiy in a mixed soivent of [bmim][BF4] with r-BuOH, while no reaction took place in [bmim][BF4] (Fig. 12). These results taught us that a mixed soivent system of IL with organic solvent may be a good solution if the desired reaction did not take piace in a pure IL solvent. 

Acylation of jS-D-glucose with azolides yields preferentially esterification in the 1-position of which for example, with R = C6H5 60% and with R=Ci7H35 71% yield are obtained. Azolides of sterically crowded acids [R = (C6H5)2CH or (CH3)3C] give poorer yields ( 28%).[193]... 

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