Carbohydrate sulfate esters

Su ate esters. Baumgarten showed that the reagent sulfates substances such as hydrazine, diethylamine, phenol, and naphthalene. It has been used in preparation of carbohydrate sulfate esters, sterol sulfate esters, phenol sulfate esters. 2-Hydroxy-3-alkyl-l,4-naphthoquinone antimalarials can be separated from metabolites hydroxylated in the side chain by conversion of the hydroxylated metabolites into water-soluble sulfate esters and extraction with water. Hydroxy-hydrolapachol (1), which was identified as a metabolite of hydrolapachol and which... 

Sulfoglycosphingolipids (containing one or more carbohydrate-sulfate ester groups)... 

Several anionic carbohydrate polymers (e.g., carboxymethyl cellulose, xanthomonas campestris polysaccharide, cellulose sulfate ester, etc.) do not adsorb from fresh water solutions, but their adsorption in saline solutions plays an... 

The first family is a directly sulfated CD. These molecules are easy to produce chemically and have the anionic sulfate group randomly distributed at the C2, C3, and C6 positions. The substituent is attached to the carbohydrate via a sulfate-ester linkage that may be metabolically unstable in vivo. One feature regarding this family is the negative charge of the substituent in close proximity to the carbohydrate backbone. 

The formation of sulfate esters is a major route of conjugation for various types of hydroxyl group, and may also occur with amino groups. Thus, substrates include aliphatic alcohols, phenols, aromatic amines, and also endogenous compounds such as steroids and carbohydrates (Figs. 4.56 and 4.57). 

Mamelak D, Mylvaganam M, Tanahashi E, Ito H, Ishida H, Kiso M, Lingwood C. The aglycone of sulfogalactolipids can alter the sulfate ester substitution position required for hsc70 recognition. Carbohydr. Res. 2001 335 91-100. 

A different approach to the synthesis of sulfate esters was discussed by Buncel and co-workers (97 ). The sulfate monoester was obtained after neutral or alkaline methanolysis of methyl 4-nltro-phenyl sulfate. The methoxide Ion attacks only at the alkyl carbon with the formation of dimethyl ether and 4-nltrophenyl sulfate Ion as the leaving group. Other substituted methyl phenyl sulfates have been converted to phenyl sulfates In the same manner (98). Correspondingly l,2 5,6-dl-0-lsopropylldlne-a-D-glucofuranose was reacted with phenyl chlorosulfate to give the carbohydrate... 

ESTERIFICATION Like all free OH groups, those of carbohydrates can be converted to esters by reactions with acids. Esterification often dramatically changes a sugar s chemical and physical properties. Phosphate and sulfate esters of carbohydrate molecules are among the most common ones found in nature. 

Sulfate esters of carbohydrate molecules are found predominantly in the proteoglycan components of connective tissue. Because sulfate esters are charged, they bind large amounts of water and small ions. They also participate in forming salt bridges between carbohydrate chains. 

Sulfohydrolases catalyze the hydrolysis of sulfate esters (R-O-SO ) according to the following reaction, where R-OH can be an alcohol, a phenol, a carbohydrate, or a steroid ... 

ASs are able to hydrolyze a variety of sulfate esters. Depending on the enzyme specificity the physiological substrates include, among others, small mono- and disaccharide sulfates, hydrophobic steroids, and amphiphilic sulfated carbohydrates found in glycosaminoglycans (GAGs). However, small synthetic aryl sulfates are the... 

Carbohydrates with more than six carbon atoms are rarely applied as auxiliaries or catalysts, as they must be prepared by multistep sequences. 1,4 5,8-Bis-anhydro-l,2-0-isopropylidene-8-methyl-6,7,9-trideoxy-a-D-glucononanose (43) was used as its methyl sulfate ester as a chiral alkylation reagent (Section D.1.1.2.2.), but no details of the preparation of the protected carbohydrate were given30. 

This approach was first used for sulfate ester protection in carbohydrates by Flitsch and co-workers. Once the sulfo groups have been protected, the free hydroxyl and carboxyl groups could be protected in organic solvents used in standard carbohydrate synthesis. This chemistry has been successfully used to selectively protect primary and secondary O- and N sulfo groups in unprotected sulfated mono- and di-saccharides in high yields. ... 

To a first approximation the exponential constant, a, in the Mark-Houwink equation reflects the solution conformation of a macromolecule. The exponential constants for the carbohydrate polymers studied, excluding the cellulose sulfate ester, are listed in Table I. Generally a value of 0.7-0.8 reflects a random coil conformation as the constant approaches or exceeds 1.0 the conformation approaches a rod-like shape. 

Sugar asters esters of mono- or oligosaccharides with organic or inorganic acids. The phosphate esters, e.g. glucose 6-phosphate, are fundamentally important in intermediary carbohydrate metabolism. Chon-droitin and mucoitin sulfates, and heparin are typical animal sulfate esters. 

The reaction is catalyzed by sulfotransferases (cf. the synthesis of the sulfate esters of carbohydrates, D 1.1, Table 22, of indole derivatives, D 21, of flavonoids, D 23.3.3 and the synthesis of glucosinolates, D 9.4). In animals sulfate esters are of significance in the elimination of secondary products (E 1). They are excreted with the urine. 

F.a.b.m.s. on multisulfated oligosaccharides from human respiratory mucous glycoprotein, combined with monosaccharide composition, allowed for determination of carbohydrate sequence, and die number and position of sulfate esters. ... 

Metachromatic Dyes. Metachromasia is a curious phenomenon consisting of a definite change in the color of Toluidine Blue O and certain other basic dyes when bound by particular acid substances. This spectacular property has been much studied but with httle clarification until recently. Lison stated that metachromasia which survived the action of alcohol and certain other extractives was due to the sulfate esters of high-molecular-weight carbohydrates 80). This view has been widely adopted. It is now clear that metachromasia is not confined to the sulfate esters of carbohydrates but is shown by the nucleic acids 81), hexametaphosphate 82), cysteic acid 83), carboxymethylcellulose 84a), and other substances. In spite of nonspecificity, the coloration of sulfated polysaccharides in tissue sections by metachromatic dyes is both useful and elegant. Toluidine blue has been used also for the detection of acidic carbohydrates on filter paper 84b). 

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