Reactions of Phosphoric Acid and its Derivatives

Reactions of Phosphoric Acid and its Derivatives.—Theoretical studies on the conformational properties of cyclic and acyclic phosphate esters, including calculations of angle and torsional strain,66 and on the reactivity of monomeric metaphosphates,67 have appeared. 

A novel demonstration of the latent reactivity of the phosphoryl bond and the apparent ease with which the number of ligands around the phosphorus atom can change under very mild conditions is provided by the hydrogen phosphonate (100), prepared from catechol and phosphorous acid or PC13. When treated with DCC, 

When the monosodium salts of uracil and similar pyrimidines react with diphenyl phosphorochloridate, phosphorylation takes place on oxygen unless other suitable nucleophilic centres are present and free.69 The reaction between the sodium salt of a 1,3-dicarbonyl compound and diethyl phosphorochloridothionate yields the Z-vinylphosphorothionate if the tetrabutylammonium salt is employed, the product has E geometry. This phenomenon has been interpreted in terms of the shape of the 

Phosphorylation of phenolate anions with dimethyl phosphorochloridothionate in water-dichloromethane systems normally gives large amounts of dithiopyrophos-phate because of extensive hydrolysis of the phosphorus chloride, but in the presence of tetrabutylammonium salts and 1 % imidazole, phosphorylation of the phenolate anion is complete. The explanation lies in an evident combination of activation of acylating agent (by imidazole) and of nucleophile (by phase-transfer catalysis).71 

Interest in solvolysis studies of phosphate esters appears to have sagged during the year, but such studies as have appeared include those on the acid-catalysed hydro- 

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