Dialkyl hydrogen phosphites

Property Dimethyl Hydrogen Phosphite Diethyl Hydrogen Phosphite Dibutyl Hydrogen Phosphite Bis (2 -ediylhexyl) Hydrogen Phosphite 

Odor mild. mild. mild. mild, suggestive 

Toxicity (single dose oral LOgg, rats), mg/kg 3,050 1,000 3,900 11,900 

Proper Trimethyl Phosohite Triethyl Phosphite Tris (2 -chloroeth Phosohite 

Appearance colorless liquid colorless liquid colorless liquid 

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The unsuhstituted hydrogen atom of the dialkyl hydrogen phosphites can be readily replaced by chlorine, and thence by many other substituents including fluorine. 

Triethyl phosphite can be obtained from Virginia Carolina Chemical Corp., Eastman Kodak Co., Aldrich Chemical Co., K and K Laboratories, and Matheson, Coleman and Bell. The presence of dialkyl hydrogen phosphite or trialkyl phosphate is not deleterious, but a correction for assay is required. Fractionation readily separates triethyl phosphite (b.p. 48-49°/ll mm.) from diethyl hydrogen phosphite (b.p. 72°/ll mm.) and triethyl phosphate (b.p. 90°/10 mm.). The presence of amines and amine hydrochlorides may seriously interfere with the alkylation, especially in the case of trimethyl phosphite (see Table I). The checkers redistilled triethyl phosphite obtained from Matheson, Coleman and Bell. 

Koh, Y.J. and Oh, D.Y., A new synthesis of (f-ketophosphonates from aryl epoxy sulfones and dialkyl hydrogen phosphite, Tetrahedron Lett., 34, 2147, 1993. 

Tewari, R.S. and Shukla, R., Organophosphorus compounds. Addition reaction of 0,0-dialkyl hydrogen phosphites with substituted aromatic and long chain aliphatic aldehydes, Labdev, Part A, 9,112,1971. 

These compounds can be prepared by the action of bromine on a trialkyl phosphite,2 but a more satisfactory method recently worked out by Goldwhite and Saunders3 consists in treating the dialkyl hydrogen phosphite with iV-bromosuccinimide. In this way dimethyl, diethyl w-propyl and isopropyl phosphoro-bromidates have been obtained as pure liquids by distillation at very low temperature. When kept at ordinary temperatures, they gradually decompose with the evolution of the corresponding alkyl bromide. 

Dialkyl hydrogen phosphites are alkylated in high yield under basic liquiddiquid phase-transfer catalytic conditions via the Michaelis-Becker reaction to yield dialkyl alkylphosphonates without serious side reactions [16, 17]. 

Nishiwaki, T. The reactions of dialkyl hydrogen phosphites with alkyl vinyl ethers. Tetrahedron 21, 3043 (1965). — Gas Chromatog. Abstr. 1966, 631. 

Bonds to Oxygen.—Compounds of Lower Oxidation State. Mixed sulphur-phosphorus anhydrides result when sulphonic acids and dialkyl hydrogen phosphites react according to equation (17).448 Further work on the preparation of trimethylsilyl esters of phosphorous acids has been carried out by... 

Opaleva, E.N.. Dogadina, A.V., and lonin, B.L, Reaction of dialkyl hydrogen phosphites with halogen-containing alkenes and alkynes in the presence of potassium fluoride, Zh. Obshch. Khim., 65, 1467, 1995 Russ.. 1. Gen. Chem. (Engl. Transl.), 65, 1344, 1995. 

Yurchenko, R.L, Klepa, T.L, Lozovitskaya, O.V., and Tikhonov, V.P., Phosphorylated adamantanes. Part 5. Some reactions of adamantane-containing dialkyl hydrogen phosphites, Zh. Obshch. Khim., 53, 2445, 1983 J. Gen. Chem. USSR (Engl. Transl.), 53, 2206, 1983. 

Pudovik. A.N., and Khusainova, N.G., Addition of alcohols, amines, and dialkyl hydrogen phosphites to esters of y. y-dimethylaUenylphosphonic acid, Zh. Obshch. Khim., 36, 1236, 1966 Chem. Abstr., 65, 16994h. 1966. 

Polozov, A.M., Polezhaeva, N.A., Mustaphin, A.H., Khotinen, A.V., and Arbuzov, B.A., A new one-pot synthesis of dialkyl phosphonates from diazo compounds and dialkyl hydrogen phosphites. Synthesis, 515, 1990. 

Pudovik, A.N., Moshkina, T.M., and Konovalova, I.V., New method of synthesis of esters of phosphonic and thiophosphonic acids. Part 31. Addition of phosphorous and hypophosphorous acids, dialkyl hydrogen phosphites, and esters of phosphonoacetic acid to esters of maleic acid, Zh. Obshch. Khim., 29, 3338, 1959 Chem. Abstr, 54, 152231, 1960. 

The kinetics of the additions of dialkyl hydrogen phosphites to enamines and to 280... 

Carbon-phosphorus bonds can be formed by the addition of dialkyl hydrogen phosphites or alkyl hydrogen phosphinates to activated ethylenic compounds. ... 

With alcohols of normal reactivity, the product is often mainly dialkyl hydrogen phosphite (6.310). This can be made np to 85% yield, by adding PCI3 to a mixture of methanol and a higher alcohol at -5°C. The methyl and hydrogen chlorides are then removed by heating under reduced pressure on a steambath. 

The large solubility (xhq = 2.35 at 10 C) of HCl in tri-n-butyl phosphate is in accord with its description as a strongly basic solvent [Tuck and Diamond (1958) ]. Trialkyl phosphites of ordinary reactivity, e.g., (n-BuO)3P, quickly react at room temperature with HCl to give the dialkyl hydrogen phosphite and alkyl chloride. This reaction does not occur with triphenyl phosphite (xhci = 0.69 at 10°C) and has a low probability of occurrence for tris(trichloroethyl) phosphite (xna = 0.46) at 10 C. The Xhci value for phenol is 0.09 and that for CI3CCH2OH is 0.087 at 10°C it therefore appears that the lone pair of electrons on phosphorus in these phosphites have electron-donor function, and indeed the postulated mechanism for the quick reaction between the n-butyl phosphite and hydrogen chloride is based on this effect. The Xhci value for dialkyl hydrogen phosphites of ordinary reactivity is about 2 at 10°C. 

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