Phosphoramidic acid,

The classical Stokes method1 for the preparation of phosphor-amidic acid and its salts entails a three-step procedure with the use of organic intermediates. Ammonium hydrogen phosphor-amidate, NH4HPO3NH2, however, is prepared more conveniently and in higher yield by the simple reaction of phosphoryl chloride with aqueous ammonia. The acid salt is stable and nonhygroscopic, and it is readily converted to the free acid or to other salts of the acid. 

Reagent-grade phosphoryl chloride (18.3 ml., 0.2 mole) is added, dropwise and with vigorous stirring, for about 5 minutes to 300 ml. of an ice-cold 10% aqueous ammonia solution (1.5 moles NH3). There is some fuming and evolution of heat, after 

A stirred solution of 11.4 g. (0.1 mole) of the ammonium acid salt in 150 ml. of water is cooled to 0° in an ice bath, and 50 ml. of 25% HC104 (prepared by diluting 25 ml. of reagent 70% HC104 to 100 ml.) is added dropwise. The acid solution is diluted immediately with 1 1. of ethanol and allowed to stand in the ice bath for 30-60 minutes to induce crystallization. The product is collected, washed successively with alcohol and ether, and air-dried. Yield is 7.5 g. (77%). Anal. Calcd. for H2P03NH2 N, 14.44 N in NH4, 0.00 P, 31.93. Found N, 14.4 N in NH4, 1.3 P, 31.5. 

1 The checkers found that the longer time was required for high yield. 

NH4HP03NH2 + 2K0H - K2P03NH2 + 2H20 + NH3 K2P03NH2 + CH3C02H - KHPOaNH, + CH.COsK 

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Diesters of phosphoramidic acid are converted to the corresponding isocyanates by phosgene but with A-substituted derivatives the phosphoramidic chlorides are formed. In a similar reaction oxalyl chloride... 

Under the agreed system, (XVIII) now becomes phosphoro-chloridic acid and (XIX) is phosphoramidic acid. The contro-... 

Relatively low molecular weight polymers include R1R2P(0)(N=PR1Ra) n-PRxR2OH (R1, R2 included alkyl, aryl, and alkoxy)175 and phosphoramidic acids from the hydrolysis of (NPC12)W,178 the latter of which form hydrophobic materials. 

Diethyl decylphosphoramidate Phosphoramidic acid, decyl-, diethyl ester (9) (53246-96-1)... 

A more complex pathway of activation is seen in N-amino acid derivative of phosphoramidic acid diesters of antiviral nucleosides, as exemplified by prodrugs of stavudine (9.79, Fig. 9.14) [153 -155], The activation begins with a carboxylesterase-mediated hydrolysis of the terminal carboxylate. This is followed by a spontaneous nucleophilic cyclization-elimination, which forms a mixed-anhydride pentacycle (9.80, Fig. 9.14). The latter hydrolyzes spontaneously and rapidly to the corresponding phosphoramidic acid monoester (9.81, Fig. 9.14), which can then be processed by phosphodiesterase to the nucleoside 5 -monophosphate, and by possible further hydrolysis to the nucleoside. 

Phosphoramidic acid forms colorless, prismatic crystals the x-ray diffraction2 and infrared absorption4 data have been reported. The compound is easily soluble in water, but the aqueous solution hydrolyzes to ammonium dihydrogen phosphate. It is stable in sealed containers, but it converts on heating to an ammonium polyphosphate.5 An unstable monohydrate of phosphoramidic acid has been described.2... 

SYNS AC 47470 AMERICAN CYANAMID CL-47470 CL-47,470 CYCLIC PROPYLENE piETHOXYPHOS-PHINYL)DITHIOIMIDOCARBONATE CYTROLANE p,p-DIETHYL CYCUC PROPYLENE ESTER of PHOSPHONODITHIOIMIDOCARBONIC ACID DIETHYL (4-METHYL-l, 3-DITHIOLAN-2-YLIDENE)-PHOSPHOROAMIDATE EI-47470 DENT25,991 MEPHOSFOLAN (4-METHYL-l,3-DITHIOLAN-2-YLIDENE)PHOSPHORAMIDIC ACID, DIETHYL ESTER... 

METHYL DIPYRIDO(l,2-a 3, 2 -d)IMIDAZOL-2-AMINE see 7UCS250 (4-METHYL-1.3-DITHIOLAN-2-YLIDENE)PHOSPHORAMIDIC ACID, DIETHYL ESTER see DHH400... 

Hydrolysis of phosphoramidic acid (NH2-P03H2) has been studied " in the acidity range pH 2-8, in aqueous solution and in some mixed solvents. Reaction appears to occur through the mono-anion, the neutral molecule and through a protonated species (rate equation (1) and Table 13). 

RATE COEFFICIENTS AND PRODUCTS FOR REACTION OF PHOSPHORAMIDIC ACID... 

RATE COEFFICIENTS FOR REACTION OF THE MONO-ANION OF PHOSPHORAMIDIC ACID WITH VARIOUS BASES AT 25 °C ... 

C8H9N02 4-(aminomethyl)benzoic acid 56-91-7 518.92 45.705 2 13838 C8H10CI2NO3 ethyl phosphoramidic acid 2,4-dichlorophenyl 36031-66-0 440.15 38.165 1,2... 

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. 

PHOSPHORAMIDIC ACID, (4-METHYL-1,3-OITHIOLAN.2-YLIDENE)-, DIETHYL ESTER PHOSPHONODITHIO-, CYCLIC PROPYLENE P.P-DIETHYL ESTER IMIDOCARBONIC ACID... 

Dimethylphosphoramidate N,N-Dimethylphosphoramidate Dimethyl phosphoramidic acid c2h8no3p 33876-51-6 Hydrolysis of GA... 

The formation of dialkyl phosphoramidates from trialkyl phosphites and benzothiazol-2 1 sulphenamides has been discussed. (Diaryloxyphosphlnyl)phosphoramidic acids have been prepared by a short conventional sequence.A convenient one-pot synthesis of 1,3-dihydro-l,3,2-diazaphosphole 2-oxides (90)... 

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