Phosphate esters naturally occurring

Some esters of inorganic acids such as dimethyl sulfate are used as reagents m syn thetic organic chemistry Certain naturally occurring alkyl phosphates play an important role m biological processes... 

The largest-volume phosphoms compounds are the phosphoric acids and phosphates (qv), ie, the oxide derivatives of phosphoms ia the + 5 oxidation state. With the exception of the phosphoric acid anhydride, P O q, and the phosphate esters, these materials are discussed elsewhere (see Phosphoric acids and phosphates). An overview of phosphoms compounds other than the phosphoric acids and phosphates is given herein. These compounds constitute a large variety of phosphoms compounds that are either nonoxide derivatives or derivatives of phosphoms ia oxidation states lower than + 5. These phosphoms compounds are manufactured only from elemental phosphoms (qv) obtained by reduction of naturally occurring phosphate rock (calcium phosphate). 

The phosphate esters and, to lesser extent, the sulphate esters of monosaccharides are very important naturally occurring derivatives. Metabolism of carbohydrates involves the formation and interconversion of a succession of monosaccharides and their phosphate esters of which glucose-1-phosphate and fruc-tose-6-phosphate are important examples. The sulphate esters of monosaccharides or their derivatives (usually esterified at carbon 6) are found in several polysaccharides, notably chondroitin sulphate, which is a constituent of connective tissues. 

Fig. 4 Lerner s group used phosphonate [3] as the hapten to raise an antibody which was capable of hydrolysing the ester [5] shown alongside it. Schultz found that naturally occurring antibodies using phosphate [4] as their antigen could hydrolyse the corresponding p-nitrophenyl choline carbonate [6]. (Those parts of haptens [3] and [4] required for antibody recognition have been emphasized with bold bonds.)...

Muhrbeck, R, Eliasson, A. -C. (1991). Influence of the naturally-occurring phosphate-esters on the crystallinity of potato starch. J. Sci. Food Agric., 55, 13-18. 

Many monosaccharides and their derivatives occur naturally in a form in which one or more of the hydroxyl groups has been substituted by a phosphate or a sulfate group. These are known as esters. In general, the phosphate esters are found as components of metabolic pathways within cells, whereas the sulfate esters are found in oligosaccharides and polysaccharides occurring outside cells. 

Two phosphate esters and two sulfate esters of monosaccharides that occur naturally are fructose 1,6-bisphosphate and 6-phosphogluconate (for both, see Chap. 11) and D-galactose 4-sulfate and N-acetylgalactosamine 4-sulfate. 

The commonest naturally-occurring inositol is myu-inositol, and its structure is readily memorised because in the preferred conformation only one hydroxyl group is axial. Its 1-L phosphate ester is biosynthesised from its isomer glucose-1-phosphate by an oxidation-intramolecular aldol condensation-reduction sequence, see Section 6.8.4. 

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