Phenylphosphoramidic acid

The parent phenylphosphoramidic acid, PO(NHPh)(OH)2, was obtained by a method which consisted in the ready hydro-gmolysis of dibenzyl phenylphosphoramidate. An attempt to prepare dibenzyl p-dimethylaminophenylphosphoramidate by the action of AA -dimethyl-p-phenylenediamine on dibenzyl jhosphorochloridate gave only an oil. When, however, a mixture of the amine, dibenzyl hydrogen phosphite, and trichloro-Ixomomethanewas used, a good yield of thedibenzylp-dimethyl-aminophenylphosphoramidate was obtained. It is a crystalline solid which causes severe dermatitis the irritation develops slowly and with some individuals persists for weeks. 

Nitration of diethyl AT-phenylphosphoramidate and diethyl phenyl phosphate in acetic anhydride or sulphuric acid yields considerable amounts of the m-nitro-... 

In a nitric-sulphuric acid mixture at 0 °C, the diethoxyphosphinylamino group in dialkyl A -phenylphosphoramidates is mostly meta directing, although with substantial para directing ability, whereas the dimethoxyphosphinothioyl group is almost completely para directing. ... 

However, the use of phenyl )V-phenylphosphoramidochloridate as a condensing agent for carboxylic acids and amines yields carboxamides in a one-step method (eq 7). The amide (12) is prepared from the carboxylic acid, 2 equiv of triethylamine, 1 equiv of amine, and 1 equiv of reagent (1) and isolated by filtration or evaporation of solvent and washing with water. Once again, a mixed anhydride intermediate (13) is presumed, which results from nucleophilic attack by the carboxylate anion on the phosphorus atom with elimination of a chloride ion a further nucleophilic attack by the amine on the carbonyl group of (13) and breakdown of the complex yields the amide (12) and phenyl Af-phenylphosphoramidate (14) which can be recycled to (1) by reaction with phosphorus pentachloride. 

---