Phosphorous azolides

Analogously to the phosphorylation of alcohols with phosphoric azolides the phos-phinylation is carried out by means of phosphinic azolides (CH2CI2/C2H5OC2H5). In the following case a I2/C2H5OC2H5) protonated diphenylphosphinic imidazolide is used to give the allylic diphenylphosphinic esters in good yields ... 

Instead of CDI, carbonyl-, thiocarbonyl- or sulfinyldibenzotriazole have also been used for formation of the nucleoside phosphoric azolide.1551... 

Nucleoside triphosphates are prepared analogously to the diphosphates by the methods a, b, c, and d, representing conversion of a nucleoside phosphoric azolide with inorganic pyrophosphate (Method a), of a nucleoside diphosphoric azolide with inorganic phosphate (Method b), of a phosphoric bisazolide with a nucleoside diphosphate (Method c), and of a diphosphoric bisazolide (bisazolide of pyrophosphoric acid) with a nucleoside phosphate (Method d). 

Mixed anhydrides between phosphoric, phosphonic, and phosphinic acids on one side and sulfonic or carboxylic acids on the other are conveniently prepared via phosphor-azolides.[150]... 

Besides CDI, other azolides such as A N -oxalyldiimidazole, AyST-carbonyldi-1,2,4-triazole, MN -oxalyldi-1,2,4-triazole, and phosphorous and phosphoric imidazolides have been used in the synthesis of peptide bonds, as displayed in Table 5-4. 

Phosphitylation with Azolides of Phosphorous Acid Synthesis of Oligonucleotides... 

The condensation reactions are preferentially carried out in pyridine. As reactive species for phosphorylation of the nucleoside R OH (synthesis of a phosphortriester), the phosphoric acid azolide has been assumed. The mixed phosphoric sulfonic anhydride and a pyrophosphate tetraester have been suggested as intermediates leading to the phosphoric acid azolide. 

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