Diphosphate monoesters

Access to diphosphates (pyrophosphates) and triphosphates is provided through the reaction of phosphoric mono- or diimidazolides with a monoester phosphate. 

Another route to such nucleoside diphosphates starts from imidazolides of phosphoric acid monoester and nucleoside phosphates ... 

Although it is convincing that metaphosphate ion is not a free intermediate in substitution reactions in aqueous solution, this does not exclude the possibility of reactions of related species proceeding via analogous intermediates. Reactions of thiophosphate monoesters are more rapid than those of phosphate monoesters. If three sulphur atoms replace three of the oxygens of metaphosphate, a stable salt can be isolated (Roesky et al, 1986). Harnett and Lowe (1988) examined the stereochemical course of the non-enzymic hydrolysis of adenosine (P- O, thio) diphosphate in In... 

TOBACCO [NicoTiANA TABACUM L.) Fractions M-Ia and M-Ib from acid phosphatase of tobacco cells did not hydrolyse phosphate monoesters except para-nitrophenyl phosphate, but hydrolysed phosphoric anhydrides (inorganic pyrophosphate, thiamine pyrophosphate, nucleoside di- and triphosphates). In addition, both fractions hydrolysed bis-para-nitrophenyl phosphate. Fraction M-II, a non-specific acid phosphatase, had broad substrate specificity it hydrolysed pyrophosphate, thiamine pyrophosphate, uridine diphosphate, adenosine triphosphate, uridine triphosphate, and cytidine triphosphate, at rates similar to para-nitrophenyl phosphate (Ninomiya et al., 1977). 

Prominent amongst the many nucleoside polyphosphates (nucleoside anhydrides) which have been isolated and studied are triphosphate monoesters of type (10.101a) and diphosphate esters of type (10.101b) (R = nucleoside or other organic groups). Many anhydrides of these types have been identified and isolated from natural sources, and some have been obtained by laboratory synthesis. 

Ribonucleic acid is thought to possess a highly branched structure. Cleavage about a branch point in the manner illustrated in (VIII) would give the pyrimidine nucleoside diphosphates discussed above. Ribonucleic acid also contains a number of phospho-monoester end groups which are susceptible to acid prostatic phosphatase and certain other monoesterases. A great deal has been learned of ribonucleic acid structure... 

Separation by anion exchange resins is useful both for analytical and for preparative purposes . The separation of diphosphates from monophosphates is easy and under certain conditions the monoesters can be separated from each other. Good results have been obtained by using borate , so that compounds as similar as ribose 2-phosphate and ribose 3-phosphate have been separated. 

Figure 9 Chemical structures of simple monoesters of triphosphate (R-TP ), diphosphate (R-DP ), and monophosphate (R-MP ).

Nucleotide derivatives. Dry adenosine-5 -phosphoric acid stirred with -carb-ethoxy-a-ethoxyvinyl diethyl phosphate and tri-n-butylamine in abs. dimethyl-formamide until dissolved after 2-3 days, dil. with acetone and the product precipitated with a soln. of anhydrous Nal in acetone Na P -(5 -adenosyl) P -diethyl diphosphate (Y 87 % as the monohydrate) warmed 3 hrs. at 50° in abs. methanol-pyridine, and the product isolated as the NH4-salt NH4 5 -adenosine methyl phosphate (Y 79.2% as the monohydrate).—Pyrophosphoric acid esters react with alcohols, amines, and acids so that the monoester part appears in the product. The adenosine-5 -phosphoric acid group in the intermediate triester is activated and can be easily combined with various nucleophiles. F. e. without isolation of the intermediate s. F. Cramer and R. Witt-mann. B. 9A, 328 (1961) s. a. B. 94, 322 dimethylformamide as phosphorylation catalyst s. B, 94, 989. 

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