Phosphate diesters, synthesis

Approaches to the synthesis of glycosyl phosphate diesters as constituents of glycopolymers of the outer membrane of bacteria, yeasts and protozoa and the latest achievements in the field have been profoundly reviewed and will not be covered in this chapter.1,2... 

Molenveld P et al (1999) Dinuclear and trinuclear Zn(II) calix[4]arene complexes as models for hydrolytic metallo-enzymes. Synthesis and catalytic activity in phosphate diester transesterification. J Org Chem 64 3896-3906... 

C. Synthesis of Phosphate Diesters Chiral by Virtue of Oxygen Isotopes and of... 

Ribonucleic Acid. RNA yeast nucleic acid. Polynucleotide directly involved in protein synthesis found in both the nucleus and the cytoplasm oi cells. Description of components of RNA see Nucleic Acids. The Four primary nucleosides are adenosine, guanosine, cytidine and uridine minor nucleosides are also found. The nucleosides are linked by phosphate diester bonds from the 3 -hydroxyl of one D -ribose to the 5 -hydroxyl of the next. The secondary structure of RNA is that of an incompletely Organized single-stranded polynucleotide consisting of some areas with helical structure alternating with non helical lengths. Compere Deoxyribonucleic Acid (DNA). Structure Brown,... 

Ribonucleic acid (RNA) Phosphate diester Polynucleotide involved in protein synthesis. ... 

In the early solution-phase synthesis of oligonucleotides, coupling of phosphate diesters was used. A mixed 3 -ester with one aryl substituent, usually o-chlorophenyl, was coupled with a deprotected 5 -OH. The coupling reagents used were sulfonyl halides, particularly 2,4,6-triisopropylbenzenesulfonyl chloride. The reactions proceed by... 

Phenyl phosphorodichloridate 163) is useful in the synthesis of asymmetric phosphate diesters such as that of the phosphatide shown below. 

Silnikov described a synthetic route to prepare over fourty 5 -triphosphate dinucleotides with modified carbohydrate-phosphate backbones with the general structure shown [65]. This route employed a combination of solution phase synthesis of the nucleoside dimers followed by the introduction of the triphosphate moiety. The dimers were synthesised from the partially protected nucleoside and 3 -0-/)-chlorophenyl-nucleoside phosphate diester in the presence of 2,4,6-triisopropylbenzenesulfonyl chloride and A -Me-imidazole in pyridine. The pyrophosphate was introduced in a stepwise manner by initial deprotection of the primary alcohol followed by reaction with phosphorus oxychloride in pyridine with subsequent addition of the tetrabutylammonium salt of inorganic pyrophosphate in acetonitrile. 

The jS-cyanoethyl group has been employed for the protection of phosphate diesters in the synthesis of deoxyribo- [34] and ribo-oligonucleotides [35]. It is introduced using a procedure similar to Fig. 6.11b, and is selectively removed on treatment wdth sodium hydroxide. In the synthesis of ribo-oligonucleotides protection by the phenyl group, also alkali-labile, has been described [36] (Fig. 6.14). It is introduced as in Fig. 6.11a. 

Several alternative procedures have been developed for chemical synthesis of 41. Acetals of the dimer of 47 can be phosphoryated using phosphoroxy chloride [184] or diphenyl chlorophosphate [185], or by phosphitylation then oxidation [186]. After phosphate deprotection, free 41 is obtained, by acid hydrolysis, in overall yields of up to 60%. New procedures have recently been developed by controlled successive substitutions of dibromoacetone [187, 188] or by controlled hydrolysis of a cyclic phosphate diester of 47 [189]. 

Chen, C.-J., Kane, R. R., Primus, F. J. et al. 1994. Synthesis and characterization of oligomeric n/do-carboranyl phosphate diester conjugates to antibody and antibody fragments for potential use in boron neutron capture therapy of solid tumors. Bioconjugate Ghent., 5, 557-64. 

Ribonucleoside H-phosphonates were introduced by Todd in 1957 to prepare diribonucleotide phosphate diesters (1). The H-phosphonates were activated for condensation with diphenyl chlorophosphate, and this activator was later extended to the synthesis of deoxyribonucle-otide dimers (2). Activation of deoxynucleoside H-phosphonates with acyl chlorides allows for the synthesis of oligodeoxynucleotides greater than 100 bases in length (3,4). Since these initial results, a number of laboratories have used acyl chlorides and nucleoside H-phosphonates in the synthesis of oligodeoxynucleotides (5-9). This chemistry has also been extended to the synthesis of phosphate analogs of oligodeoxynucleotides (10-16). 

Some of the concepts most attractive for the simplification of oligonucleotide synthesis and, thus, also for reducing cost and effort of potential large-scale preparations, come from a combination of two of the three operations essential for conventional chain-elongation. Although the combination of protection and activation principles plays a minor role in phosphate-diester and phosphate-triester chemistry, this is the basis of success of the phosphoramidite synthesis (23,24). The relative stability of nucleoside phosphoramidites at room temperature and their fast and efficient activation by tetrazole (23) (see also 25 for mechanistic studies) are essential to today s most utilized process of internucleotide bond formation. 

There are mainly two types of nucleic acids, namely deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Primarily nucleic acids serve as repositories and transmitters of genetic information. The DNA is organised into genes which are the fundamental units of genetic information. These genes control protein synthesis. Components of nucleic acids are sugar, base and phosphate diester molecules nucleic acids are polymers of nucleotides held by 3 and 5 phosphate bridges. 

Amin S, Voss DA Jr, Horrocks WD Jr, Morrow JR. Restoration of catalytic activity by replacement of a coordinated amide group synthesis and laser-induced luminescence studies of the phosphate diester transesterification catalyst [Eu(NBAC)]. Inorg Chem. 19% 35(26) 7466-7467. 

Given the low natural abundance of O and 0, chemical methods for the synthesis of phosphate esters that are chiral by virtue of oxygen-isotope substitution must allow for the introduction of any oxygen isotope from (ideally) the commercially available forms of the heavy isotopes H2O, CO2, or O2. In addition, the substrates of the phosphoryl and nucleotidyl transfer reactions include three types of structurally and chemically different phosphates, almost all of which are polyhydroxylic phosphate monoesters, such as sugar phosphates and mononucleotides, phosphate diesters, such as 3, 5 -cyclic nucleotides and oligonucleotides, and phosphate anhydrides... 

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