Phosphoramidates phosphorodiamidates

BIS(2-CHLOROETHYL)PHOSPHORAMIDE-CYCUC PROPANOLAMIDE ESTER see CQC650 N,N-BIS(2-CHLOROETHYL)-N -3-PHOSPHORODIAMIDIC ACID HYDROXYLPROPYLCYCLOHEXYLAMINE SALT see CQNOOO... 

The resulting names are quite diflFerent from the names previously in use, but they do have the advantage of usually starting with "phosph (good for indexes and other records). Thus thiophosphoric acids became phosphorothioic, phos-phorodithioic, phosphorotrithioic, and phosphorotetrathioic acids. Amidophos-phoric acids became phosphoramidic acid and phosphorodiamidic acid. For the halogen-substituted acids such names as phosphorochloridic acid and phosphoro-dichloridothioic acid are used. 

Treatment of thymidine 5 -phosphorodiamidate (54) with pyrophosphate in anhydrous DMF leads to the formation of P -(thymidine-5 )-P -aminotriphosphate (55) in good yield. The compound is sufficiently stable to be purified on DEAE-Sephadex at low temperature. In acid, conversion into TTP is quantitative, but in ammonia, thymidine-5 -phosphoramidate and pyrophosphate are formed. Treatment with alkaline phosphatase cleaves (55) to the phosphoramidate. Nucleophilic attack takes place very easily in anhydrous DMF at ambient temperature, (55) is in equilibrium with (56) and pyrophosphate. 

The reactions between a,j -unsaturated carboxylic acids and phosphoramidous diesters or phosphorodiamidous esters are, as might be expected, more complex than those with phosphorus(III) triesters. The products from propenoic acid and EtOP(NEt2)2 include the amides 449 and 450 (in 21% total yield), the phosphonic amide 451 (26%) and N,N-... 

Phosphoramidates and phosphorodiamidates can be conveniently prepared by reacting ammonia with the corresponding phenyl phosphorochloridates (7.53) and (7.54). The latter are made from phenol and POCI3 (5.294) and (5.295). 

Phosphoramidic acid is somewhat stronger than phosphorodiamidic acid (Table 5.24). If phosphoramidic acid is heated for several hours at 100°C, it isomerises to a very soluble ammonium polyphosphate, by a process which is probably connected with zwitterion formation (7.59). If carbon dioxide is passed into a solution of Na2P03NH2, the relatively insoluble monosodium salt is obtained, which contains the zwitterion (7.60a). Isoelectronic sulphamic acid (7.60b) also exists as a zwitterion [9]. 

Phosphoryl triamide, PO(NH2)3, can be made by the direct reaction of liquid ammonia with phosphoryl chloride (7.48), or with triphenyl phosphate (7.64). It forms colourless needles which are very soluble in water, but insoluble in most organic solvents. Prolonged heating results in transformation into polymeric material. Dilute acid hydrolysis or atmospheric moisture will yield mono-ammonium phosphoramidate, while with dilute NaOH, sodium phosphorodiamidate is formed (7.65)... 

The new bidentate phosphoramide (106) derived from 2,2-bispyrrolidine provided the highest yield and enantioselectivity in the addition of various allylic trichlorosilyl species to aromatic and unsaturated aldehydes (Scheme 36). It has been shown that phosphorodiamidic acid is a novel structural motif of Bronsted acid catalysts (107)... 

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