Inositol Phosphates and Phospholipids

Several review articles and books concerning the synthesis of inositol phosphates and phospholipids are available.14 This text does not cover all reports on the synthesis of inositols but principally deals with synthetic strategies and total synthesis of inositol derivatives which involve selective reactions such as stereoselective and regioselective ones. 

The reaction of 1,2-cyclohexylidene-myo-inositol 47a with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPS-CI2) takes place in a completely regioselective manner to afford the 3,4-disiloxane derivative 76 in quantitative yield. 5- - Compound 76 has been shown to be a very useful synthetic intermediate by the synthesis of various inositol phosphates and phospholipids (Scheme 3-9). The usefulness... 

Phospholipids may consist of a backbone of glycerol esterified with two fatty acids and one molecule of choline phosphate in the position. Tn other phospholipids, the 3 position may be occupied by a molecule of ethanolamine phosphate, serine phosphate, or inositol phosphate. A phospholipid containing choline phosphate is called phosphatidylcholine one containing ethanolamine phosphate is called phosphatidylethanolamine. Generally, the fatty acids esterified as triglycerides contain up to one double bond, whereas those esterified as phos-... 

There are multiple phospholipase C s (PLCs) that are linked via G-proteins to neurotransmitter receptors. PLCs split the link between the Sn3 carbon and the phosphorus, thus generating two molecules the headgroup phosphate and diacylglycerol (DAG). PLCs particularly act on inositol phospholipids, generating inositol phosphates and DAG. As in the PLA2 cycle, both of these products are active signal transduction molecules. Again, the cycle must be terminated as shown in Fig. 2, by means of inositol phosphatases and DAG kinases. 

Bruzik and Tsai applied the protection strategy using the TIPS group to the synthesis of various optically active precursors for inositol phosphates and inositol phospholipids from 1,2-camphor ketal 65 of myo-inositol. ... 

Solution nuclear magnetic resonance (NMR) spectroscopy was introduced by Newman and Tate (1980) to define the structural composition of soil organic phosphorus. The technique allows the identification of several inorganic phosphorus forms (phosphate, pyrophosphate, polyphosphate) and organic phosphorus forms, such as phosphate monoesters (e.g. inositol phosphates and sugar phosphates), phosphate diesters (e.g. nucleic acids, phospholipids, teichoic acids) and phosphonates. 

Methods for the quantitative chromatographic analysis of inositol phosphates and inositol phospholipids have been reviewed. ... 

A review on the application of the phosphoramidite method to the synthesis of phosphorylated biomolecules covered, inter alia, mononucleotides, glycosyl phosphates, inositol phosphates and inositol phospholipids. Dibenzyl iVA -diethyl phosphoramidite has been recommended as an efficient and convenient reagent for the preparation of dibenzyl glycosyl phosphites. Bicyclic phosphorylated carbohydrates have been reviewed (40 pp., 60 refs.) in Russian. The rearrangement of a sugar bicyclothiophosphate to a thiosugar bicyclophosphate is covered in Chapter 11. 

Phosphate esters and anhydrides dominate the living world. Major areas of synthetic interest include oligonucleotides (polymeric phosphate diesters), phospho-rylated peptides, phospholipids, glycosyl phosphates, and inositol phosphates. ... 

Peptideglycan biosynthesis Metabolism of Complex Lipids Glycerolipid metabolism Inositol phosphate metabolism Sphingophospholipid biosynthesis Phospholipid degradation Sphingoglycolipid metabolism Prostaglandin and leukotriene metabolism... 

On hydrolysis of the phosphatides, myo-inositol monophosphate—and, from a brain phosphatide, a diphosphate—is obtained but, these products have, in most cases, not been adequately characterized, and it is not yet known whether all phospholipids contain the same myo-inositol phosphate. It has been shown169-170 that the phosphate obtained by hydrolysis of liver phosphatide171 or soybean phosphatide172 is a mixture of myo-inositol 1- and 2-phosphates. A myo-inositol phosphate, of unknown constitution, was isolated173 from liver without previous hydrolysis apparently it occurs in the free state. 

Trayner-Kaplan, A. E., Harris, A. L., Thompson, B., Taylor, P., and Sklar, L. A. (1988) An inositol tetrakis phosphate-containing phospholipid in activated neutrophils, Nature 334, 353-356. 

Fig. 4. Proposed production of a glycan-inositol phosphate mediator by insulin. This summarizes Sal-tiel and Cuatrecasas concept for the production of novel mediators through insulin s action. It may, by analogy with the receptor-mediated stimulation of inositol phospholipid metabolism, involve a G-pro-tein. Here it is postulated that the putative Glns may play such a role.

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