Chlorinated carbohydrate

Despite the wide spread use of the artificial sweetener, Splenda , which is a synthetic chlorinated carbohydrate, Nature has provided very few halogenated carbohydrates. The antitumor metabolite FR 901463 (1598) was isolated from a Pseudomonas sp. along with two nonchlorinated epoxides. FR 901463 is not an isolation artifact, being present in the culture medium prior to extraction and isolation (1542-1544). 

Oscarson, S, Tedebark, U, Synthesis and acidic opening of chlorinated carbohydrate orthoacetates, J. Carbohydr. Chem., 15, 507-513, 1996. 

Replacement of acetoxy groups by chlorine Carbohydrate derivatives... 

Sucralose (also called 4,T,6 -trichloro-4,T,6 -trideoxygalactosucrose, E955) is technically a chlorinated carbohydrate, and it is made by selectively replacing three hydroxyl groups on the sugar molecule with three chlorine atoms (Figure 4A.35). 

The aromatic nature of lignin contrasts with the aliphatic stmcture of the carbohydrates and permits the selective use of electrophilic substitution reactions, eg, chlorination, sulfonation, or nitration. A portion of the phenoUc hydroxyl units, which are estimated to comprise 30 wt % of softwood lignin, are unsubstituted. In alkaline systems the ionized hydroxyl group is highly susceptible to oxidative reactions. 

It would be reasonable to expect that the decomposition of the N,N-dimethylimino ester chlorides proceeds via a bimolecular mechanism already demonstrated for the thermal decomposition of simple imino ester salts (79). In the carbohydrate series, where an isolated secondary hydroxyl group is involved, such a process would result in chlorodeoxy sugar derivatives with overall inversion of configuration, provided that the approach of the chloride ion is not sterically hindered. Further experiments are in progress in this laboratory utilizing additional model substance to establish the scope and stereochemical course of the chlorination reaction. 

Toxic compounds polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated pesticides, dioxins, veterinary drug residues, hormone residues, aflatoxins, toxic compounds in shellfish. Compoimds of nutritional significance in foods vitamins, fat, lipids, carbohydrates, protein, energy-calorific value, proximates, dietary fibre, ash. Other compounds hormones in blood serum... 

Dissolved lignin and carbohydrates Color COD AOX Inorganic chlorine compounds (e.g., chlorate (C103 ))c Water... 

The reaction of sulfuryl chloride with carbohydrates to give chloro-deoxy derivatives has been reviewed briefly in this Series.98 The reaction of sulfuryl chloride with monosaccharides has been shown to afford products in which the secondary hydroxyl groups are replaced by chlorine with inversion of configuration.68-75 Jones and coworkers reported that the reaction of methyl a-D-glucopyranoside with sulfuryl chloride and pyridine in chloroform at room temperature proceeds by way of the 4,6-bis(chlorosulfate) by an Sn2 process, with chloride as the nucleophile, to give methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside 2,3-bis(chlorosulfate).74... 

Elforts have been made to characterize the nature and content of individual components that are present in the low-molecular-mass fraction of the total mill effluents, which include the spent chlorination and alkali extraction stage liquors [2,4]. Approximately 456 types of compounds have been detected in the conventional bleach effluents, of which 330 are chlorinated organic compounds [22]. The compounds may be lumped into three main groups, namely, acidic, phenolic, and neutral (Table 2). Acidic compounds are further divided into the five categories of acids fatty, resin, hydroxy, dibasic, and aromatic acids. The most important fatty acids are formic and acetic acids. The dominant resin acids are abietic and dehydroabietic acids. Among the hydroxy acids identified, glyceric acid predominates. Dibasic acids such as oxalic, malonic, succinic, and mafic acids are derived from the lignin and carbohydrate fraction... 

R. S. Bhatt, L. Hough, and A. C. Richardson, Selective chlorination of methyl p-lactoside with mesyl chloride in DMF, Carbohydr. Res., 49 (1976) 103-118. 

Dihydro-l,2,4-oxadiazoles with hydrogen atoms in the 4- and 5-positions are readily oxidized to 1,2,4-oxadiazoles with air or potassium permanganate <87JHClOl>, chlorine <75JOC248l>, or N-bromosuccinimide <86MI 404-02>. This has been used, for example, for the preparation of oxadiazoles substituted with a carbohydrate moiety (Scheme 71) <86MI 404-02). 

Carbohydrates (see also Sugars), 77 Charcoal, 77 as a fuel, 155 effect on sensitivity, 108 sparks from, 147 Chlorate ion, 39 Chromic oxide, 115 Chlorine donors, 155... 

Similar comments apply to cyclic systems (Table 8-2). SYBYL molecular mechanics is completely unsatisfactory for establishing relative conformer stabilities, while MMFF appears to be quite well suited for this purpose. The only unsatisfactory case for the MMFF model is 2-chlorotetrahydropyran, where the noted preference for an axial chlorine (usually attributed to the anomeric effecF) is not reproduced. Caution should be exercised in the application of MMFF to carbohydrates where the anomeric effect may lead to significant conformational preferences. 

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