Pyrophosphorous acid esters

Freparation of pyrophosphoric acid esters. The reagent reacts with mono and di esters of phosphoric acid at room temperature to give the corresponding symmetrical di and tetra esters of pyrophosphoric acid. Yields are well-nigh quantitative. DCC reacts similarly but isolation of tetra-p-nitrophenyl pyrophosphate presented some difficulty owing to similar solubilities of the ester and the substituted urea. With di-p-tolylcarbodiimide in dioxane this difficulty was overcome. 

Pyrophosphoric acid esters from dialkyl phosphites ... 

Bromocyanoacetamide Mixed phosphoric acid esters and unsym. pyrophosphoric acid esters s. 18,171... 

Tetraethyl pyrophosphite Pyrophosphoric acid esters with organic dehydrating agents... 

Diphosphoric acids and esters Pyrophosphoric acid esters 20... 

Phosphoric acid diesters from phosphorodichloridates—Simultaneous removal of protective groups s. 13, 284 Pyrophosphoric acid esters... 

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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