Carbohydrates polyols 398

Lynch, B.S. Tischler, A.S. Capen, C. Munro, I.C. McGirr, L.M. McClain, R.M. Low digestible carbohydrates (polyols and lactose) significance of adrenal medullary proliferative lesions in the rat. Regul. Toxicol. Pharmac. 1996, 23, 256-297. 

Sterols, fatty acids, diacylglycerophospholipids, galactosyldiacylglycerols, sulfolipids, pheophytins, carotenoids, carbohydrates, polyols, organic acids, amino acids Lactuca sativa (lettuce) (aqueous and lipophilic extract) COSY, TOCSY, HSQC, HMBC identification and assignment 49... 

Surfactants, Renewable resources. Carbohydrates, Polyols, Oils, Fats, Cationic emulsifiers, Gemini, Bolaamphiphiles synthesis. Surface propraties. Applications... 

Liquids. Liquid enzyme formulations usually contain a significant amount of stabilizing agents, such as carbohydrates, polyols and inactive (filler) proteins. In addition, side-products from the fermentation may be present. In general, they tend to stabilise enzymes and thus their removal (e.g., by dialysis) is not recommended. The same apphes to dilution, as concentrated protein solutions are usually more stable. Liquid formulations should be stored in the cold (0 to +4°C), but avoid freezing If long-term storage is required, two options are possible (if in doubt, test both methods on a sample first and check for any loss of activity) ... 

In 1992, Ley and co-workers demonstrated the inherent selectivity of 3.3, 4.4 -tetrahydro-6,6 -bis-2//-pyran (bis-DHP) 1 for trans diequatorial vicinal diols in polyol systems in carbohydrate derivatives (Scheme 1) [26]. In a typical experiment, the carbohydrate polyol was reacted with an excess of bis-DHP 1 in refluxing chloroform and in the presence of a catalytic amount of camphorsulfonic acid to afford the corresponding dispiroketal. For representative examples see Table 1. The protection process proceeds in moderate to good yields and gives diequatorial diol protection as the major outcome in all cases. In a few cases some c/s-diol protection was noticed as a minor process when steric interactions were of lesser magnitude. 

The most general way to attach phosphine residues to carbohydrates, polyols, or PEG is allylation with subsequent free-radical addition of primary or secondary phos-phinesJ The hydroxymethylation of PH bonds is the other general method of preparation of a large number of interesting hydrophilic phosphines, some examples of which are given in Scheme 21, which were recently obtained and characterized, though they have not yet found their place in catalysis. ... 

Scheme 17 Carbohydrates/polyols reacted with the presence of the TOMPP/Pd system.

Carbohydrate (polyol) sweeteners are of great importance for nutritional reasons and because of their good taste quality. Because of the structural nature of these compounds, the inter- and intra-molecular hydrogen bonds are thought to play important roles in their activities. MD simulations in water have been carried out by Birch and co-workers in an attempt to define the SAR of some polyols. They studied sweet a-mannopyranose, its bitter anomer S-D-mannopyranose, and some related polyols. The radial distribution functions of these compounds show different and distinctive behaviors... 

Alditol (Section 25 18) The polyol obtained on reduction of the carbonyl group of a carbohydrate Aldol addition (Section 18 9) Nucleophilic addition of an aldehyde or ketone enolate to the carbonyl group of an aide hyde or a ketone The most typical case involves two mole cules of an aldehyde and is usually catalyzed by bases... 

Alditol (Section 25.18) The polyol obtained on reduction of the carbonyl group of a carbohydrate. 

In 1991, Whitesides etal. reported the first application of aqueous medium Barbier-Grignard reaction to carbohydrate synthesis through the use of tin in an aqueous/organic solvent mixture (Eq. 8.48).106 These adducts were converted to higher carbon aldoses by ozonolysis of the deprotected polyols followed by suitable derivatization. The reaction showed a higher diastereoselectivity when there was a hydroxyl group present at C-2. However, no reaction was observed under the reaction conditions when there was an /V-acctyl group present at the C-2 position. 

Labels have to avoid being misleading to the consumer. As an example some academic chemists dislike the practice of referring to substances such as sorbitol as polyols and would prefer them to be called sugar alcohols. The confusion that this would cause would be very unfortunate. Some of those who need to control their intake of small carbohydrates would be wondering if these substances are sugar or not ... 

Various individual amino acids Various carbohydrates Alcohols and polyols Surfactants... 

Table 6.9 Amino acids, carbohydrates and polyols that have found most application as stabilizers for some biopharmaceutical preparations...

Several polyols (i.e. molecules displaying multiple hydroxyl groups) have found application as polypeptide stabilizing agents. Polyols include substances such as glycerol, mannitol, sorbitol and PEG, as well as inositol (Table 6.9 and Figure 6.22). A subset of polyols is the carbohydrates, which are listed separately (and thus somewhat artificially) from polyols in Table 6.9. Various polyols have been found to stabilize proteins in solution directly, and carbohydrates in particular are also often added to biopharmaceutical products prior to freeze-drying in order to provide physical bulk to the freeze-dried cake. 

Freeze-drying is a relatively gentle way of removing water from proteins in solution. However, this process can promote the inactivation of some protein types, and specific excipients (cryopro-tectants) are usually added to the product in order to minimize such inactivation. Commonly used cryoprotectants include carbohydrates (such as glucose and sucrose), proteins (such as HSA), and amino acids (such as lysine, arginine or glutamic acid). Alcohols/polyols have also found some application as cryoprotectants. 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

Hoffmann, H. M. R. Dunkel, R. Mentzel, M. Reuter, H. Stark, C. B. W., The total synthesis of C-glycosides with completely resolved seven-carbon backbone polyol stereochemistry Stereochemical correlations and access to L-configured and other rare carbohydrates. Chem. Eur. J. 2001,7, 4771-4789. 

Concentrated aqueous salt solutions were used for dehydration of carbohydrates catalyzed by RuCh + Ag2S04 ( RUSO4 ) [47]. Such solvents may also help in constracting aqueous-organic biphasic media with good phase separation properties. Selective dehydroxylation of polyols and sugars was achieved in aqueous solutions with the use of anionic rathenium carbonyls, as well [48]. 

---