Ethyl hydrogen phosphonate

It is a useful solvent for the preparation of arylhydrazones and 2,4-dinitrophenyl-hydrazones. No catalyst is required because a trace of water hydrolyzes the reagent to the acidic ethyl hydrogen phosphonate. HP(0)(OCiH,)OH. The small volume of solvent required improves yields. Although the reaction usually is rapid at room temperature, yields may he improved by heating the mixture for I hr. on the steam bath. 

The newest active substance developed by the Rhone-Poulenc (Horriere, 1977) is ethyl hydrogen phosphonate aluminium-salt (39). Its common name is fosetyl. This fungicide is truly systemic with protectant and curative properties, primarily active against Phycomycetes fungi (Bertrand et al., 1977 Williams et al., 1977). It has been widely tested on temperate and tropical crops (Beach, 1979) and has successfully controlled many important Phytophtkora spp and downy mildew. Mixtures with... 

Synonyms Aluminum tris (o-ethyl phosphonate) Ethyl hydrogen phosphonate... 

Tetra-n-butylammonium or potassium thioacetates react with dialkyl chloro-, bromo-, or iodomethylphosphonate in THF or DME at room temperature to give dialkyl l-(acetylthio)methylphos-phonate in 59-95% yields - " Ethyl hydrogen [(aminoiminomethyl)thio]methylphosphonate can be obtained in 20-38% yields from diethyl chloro- qj- bromomethylphosphonates and thiourea on heating at 125-130°C. Subsequent treatment with NaOH gives ethyl hydrogen mercaptomethyl-phosphonate ... 

Synonyms 2-Ethylhexyl hydrogen 2-ethyl hexyl phosphonate 2-Ethyl hexyl... 

In 2014, Lee and coworkers also reported an efficient phosphaannulation by Pd-catalyzed carbonylation of C-H bonds of phosphonic and phosphinic acids for the synthesis of oxaphosphorinanone oxides (Scheme 4.29) [43]. In the reaction, AgOAc and PhI(OAc)2 gave the best result. In the transformation, ethyl hydrogen benzylphosphonate and methyl-substituted phosphonate were totally ineffective. It indicated that introduction of two substituents at the a-position was essential for successful carbonylation. Both electron-donating and electron-withdrawing groups on the aryl ring were tolerated. 

Ethyl hexyl hydrogen chloromethyl phos-phonate, in liquid-liquid extraction, 9 40 2-Ethyl hexyl hydrogen 2-ehtyl hexyl phos-phonate, in liquid-liquid extraction, 9 40 2-Ethyl hexyl hydrogen phenyl phosphonate, in liquid-liquid extraction, 9 40 Ethylsilanetriol, mono,sodium salts, 42 169 Ethynyidifluoroborane, 26 38 Etioporphyrin, 21 36 EtjSifOH), 42 228, 233 Eu "... 

Reduction of this intermediate by hydrogen transfer from 1,4-cyclohexa-diene in the presence of platinum leads to loss of the carbobenzoxy group and formation of the transient primary amine 119. The terminal primary amino group in that product then participates in a second addition-elimination sequence to form an eight-membered ring (120). Treatment of this intermediate with trimethylsilyl bromide then cleaves the ethyl ethers on phosphorus to give the free phosphonic acid and thus perzinfotel (121). ... 

Fig. 6. A stereo view of the structure of the oxyanion hole in RmL, as inferred from the structure of the complex with n-hexyl phosphonate ethyl ester. The dotted lines represent the two hydrogen bonds to the tetrahedral intermediate.

Many communications have concentrated on specific amino phosphonic acids or derivative types. Thus, esters of phosphonoaminoacetic add were obtained by the reactions between trialkyl (ethyl) phosphite and (218) and which are thought to proceed via the phosphorane (219). A sequence has been presented for the preparation of the mono- and di-benzyl esters of N-chz protected (a-aminoben-zyl)phosphonic acid. A synthesis of (aminomethylene)bisphosphonic acid from dibenzylamine, dibenzyl hydrogenphosphonate and triethyl orthoformate has been noted and the asymmetric hydrogenation of (220) in the presence of chiral phosphine catalysts yields samples of (221) with e.e.s of 63-96%. The pyrrolidine-based compound (222) has been prepared from methyl S)-N-methoxycarbonyl-4-oxo-2-pyrrolidinecarboxylate and iV-coupled 4-amino-butanal diethyl acetals were the starting materials in syntheses of the pyrrolidine-2-phosphonic add derivatives (223) in which Z represents the iV-protected amino add or peptide moiety. ... 

Acidic and basic hydrolysis of GA result in different products (Fig. 4). Under acidic conditions, ethylphosphoryl cyanidate and dimethylamine are formed under basic and neutral conditions, ethyl A,A-dimethylamido phosphoric acid and hydrogen cyanide are formed. Although the latter pathway is predominant, di-methylphosphoramidate, phosphorocyanidate, and dimethylphosphoramide cyanidate may also be formed (Sanches et al. 1993). The phosphorus-containing compounds are slowly hydrolyzed to phosphoric acid. Although theoretically possible, there is little likelihood of formation of a detectable amount of methyl phosphonic acid from GA. Hydrolysis products are listed in Table 37. 

A soln. of phenylphosphonic dichloride in bromobenzene added under Ng to a stirred slurry of 3,4-dihydroxypropiophenone in bromobenzene, refluxed 6 hrs., the bromobenzene removed by distillation, and the residue triturated with ethyl acetate 2-hydroxy-5-propionylphenyl hydrogen phenylphosphonate. Y 83%. — The intermediate cyclic phosphonate absorbs moisture from the atmosphere. F. e. s. K.D. Berlin and M. Nagabhushanam, Tetrahedron 2d, 2709 (1964). 

Hydrogenation of ketones proceeds less readily in aqueous systems, and genuine two-phase procedures are much less developed. A rare example is the hydrogenation of various substituted acetophenones with Ir- and Rh-complexes (95) of phosphonate-substituted bipyridines (Scheme 6). These reactions proceed with high 3delds at room temperature under 4 MPa H2, in water-ethyl acetate, water-diethyl ether mixtures, or without an organic solvent especially if a basic aqueous phase is used. The Rh-catalyst was recycled in the aqueous phase with only a small loss in activity. 

Metals of Valency Three and Higher.— There have been several reports of the measurement by n.m.r. of the kinetic characteristics of complexes of Group IIIA tervalent metal ions. Delpuech et al. have used the spectra associated with the A1 and nuclei to identify the species present in solutions of the metal and a number of phosphorus-containing ligands, and to measure their exchange characteristics. It appears that the major solvates of AP+ in trimethyl (TMPA) and triethyl phosphates (TEPA), dimethyl methyl- (DMMP) and diethyl ethyl-phosphonates (DEEP), and dimethyl hydrogen phosphite (DMHP) are octahedral. In each case the rate law for the exchange process,... 

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