Phosphite, triethyl

A solution of 151.8 g. (3.30 moles) of absolute ethanol (p. 142), 399.3 g. (3.30 moles) of dimethylaniline, and 200 ml. of dry ether is stirred and cooled by immersion in a water bath while a solution 

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Phosphorus trichloride reacts readily with three equivalents of an alcohol e.g, ethanol, in the presence of a tertiary amine such as pyridine, dimethyl-aniline, or diethylaniline, to form triethyl phosphite and hydrogen chloride, the latter being immediately neutralised by the tertiary amine. 

The following preparation of triethyl phosphite illustrates the interaction of phosphorus trichloride and ethanol in the presence of dimethylaniline the preparation of di-isopropyl hydrogen phosphite illustrates that of phosphorus trichloride and isopropanol in the absence of a tertiary amine. 

Triethyl phosphite is a colourless mobile liquid, insoluble in water. Trialkyl phosphites are valuable intermediates in the preparation of many organophosphorus compounds they readily form dialkyl esters of alkylphosphonic acids by the Arbusov reaction (p. 311). 

Meanwhile set up the ether distillation apparatus as used in the preparation of triethyl phosphite (p. 308). Distil off the ether and then fractionally distil the residue at water-pump pressure. The di-isopropyl hydrogen phosphite distils at 79Vi4 mm. other b.ps. are 8o°/i5 mm., 82-5°/i7 mm. Yield, 25 g., 89%. 

In the reaction described below triethyl phosphite (p. 308) is heated with ethyl iodide to give diethyl ethylphosphonate. Although theoretically a very small amount of ethyl iodide would suffice, it is advantageous to use more than the minimum amount so as to reduce the temperature of the boiling reaction-mixture. 

Common reducing agents are hydrogen in the presence of metallic or complex catalysts (e.g. Ni, Pd, Pt, Ru, Rh), hydrides (e.g. alanes, boranes, LIAIH, NaBHJ, reducing metals (e.g. Li, Na, Mg, Ca, Zn), and low-valent compounds of nitrogen (e.g. NjHj, NjHJ, phosphorus (e.g. triethyl phosphite, triphenyiphosphine), and sulfur (e.g. HO-CHj-SOjNa = SFS, sodium dithionite = Na S O. ... 

The ff-oxidation of carbonyl compounds may be performed by addition of molecular oxygen to enolate anions and subsequent reduction of the hydroperoxy group, e.g. with triethyl phosphite (E.J. Bailey, 1962 J.N. Gardner, 1968 A,B). If the initially formed a-hydroperoxide possesses another enolizable a-proton, dehydration to the 1,2-dione occurs spontaneously, and further oxidation to complex product mitctures is usually observed. 

The acylstannanes 874 and 875 are prepared by the reaction of acyl chlorides with (MciSnl - The symmetrical 1,2-diketones 877 can be prepared by the reaction of an excess of benzoyl chloride with (EtjSn) . Half of the benzoyl chloride is converted into the benzoyltin reagent 876, which is then coupled with the remaining benzoyl chloride under a CO atmosphere to afford the a-diketone 877[748], Triethyl phosphite is used as a ligand. 

Several procedures have been explored for the reductive cyclization of o-nitrostyrenes. Triethyl phosphite accomplishes this transformation by deoxy-... 

Ethyl o-nitrocinnamate (1 mmol) was dissolved in triethyl phosphite (5 mmol) and heated at 170°C for 3 h. The triethyl phosphite and triethyl phosphate were removed in vacuo. The residue w as eluted through a column of silica gel using CHCI3 and the product recrystallizcd from CHCl3-hexane. The yield was 94%. 

Thiols and phosphines add to maleic anhydride to give a-thiosuccinic anhydrides (82) and phosphoranylidene—maleic anhydride adducts (83). Triethyl phosphite [122-52-1] reacts with maleic anhydride to give the yhde stmcture (23) (84). Hydrolysis of this adduct (23) leads to succinic acid... 

Benzyl chloride readily forms a Grignard compound by reaction with magnesium in ether with the concomitant formation of substantial coupling product, 1,2-diphenylethane [103-29-7]. Benzyl chloride is oxidized first to benzaldehyde [100-52-7] and then to benzoic acid. Nitric acid oxidizes directly to benzoic acid [65-85-0]. Reaction with ethylene oxide produces the benzyl chlorohydrin ether, CgH CH20CH2CH2Cl (18). Benzylphosphonic acid [10542-07-1] is formed from the reaction of benzyl chloride and triethyl phosphite followed by hydrolysis (19). 

Few reactions of this type are recorded. The azidopyridazinone ester (349) on reduction with triethyl phosphite, hydrazine or borohydride furnished the pyrido[2,3-c]pyridazin-7-one (350) (79JHC1559), whilst an A-aminopyrido[2,3-c]pyridazine (352) resulted from the... 

Triethyl phosphite is an effective reagent for the deoxygenation of appropriate nitro (or nitroso) aromatic systems. Free nitrenes or some nitrenoid-like species may be involved, and the use of this reagent is illustrated by the examples below. It has the advantage over the azide approach in that two steps in the synthesis can be avoided. 

Treatment of the substituted azobenzene (561) with triethyl phosphite gave the triazapen-talene (563). It is likely that the 2-substituted benzotriazole (562) was initially formed which then underwent deoxygenative cyclization to (563) (74CL951). 

A similar treatment of the Schiff s base derived from 3-nitro-2-thienylcarbaldehyde (564) with triethyl phosphite gave the thieno[3,2-h]pyrazole (565) (78CC453). ... 

Cyclization onto a heterocyclic ring also readily occurs, as when the 2-substituted pyridine (566) was treated with triethyl phosphite. In this case the pyrrolopyrazole (567) was obtained (79JOC622),... 

Nitration of 3-ethyI-l,2-benzisoxazoIe 2-oxide (57) and reduction under forcing conditions with triethyl phosphite gave 6-nitro-l,2-benzisoxazoIe. In contrast, nitration of 2-ethyI-1,2-benzisoxazole gave 5-nitro substitution (Scheme 23) (80CC421). 

The oxygen of 1,2-benzisoxazole fV-oxides can be removed by treatment with triethyl phosphite (80CC42l), and the oxygen of 3,4,5-triphenylisoxazoline A-oxide with H2 catalysis and PCI5 (69JOC984). Isoxazoline A-oxide (272) reacts with styrene to give cycloadduct (273) (66ZOR2225). 

Reagent 3, bp 93-96°C (14 mm), was prepared by condensation of triethyl phosphite and cyanogen bromxle. 

Subsequently, several laboratories developed improvements in the early procedures. It was first recommended that the reaction be carried out at a low temperature ca. —T) for better results. A more notable improvement is the use of dimethylformamide-t-butanol as the solvent system, a temperature range of —20 to —25°, and the presence of triethyl phosphite during the reaction to reduce the hydroperoxide as it is formed. The triethyl phosphate which is produced is water soluble and overall yields are generally in the range of 60-70 %. 

Tricliloro-l, 2,2-trifluoroethane, 132 Tricresyl phosphates, 132 Tricyclohexyltin hydroxide, 132 Triethyl aluminum, 132 Triethylamine, 132 Triethyl phosphite, 132 Trifluorobromomethane, 132 Trifluoroethane, 132 Trifluoromethane, 132 Trifluralin, 132 Triisobutyl aluminum, 133 Trikem SA, 146... 

Pd(OAc)2, sodium 2-methylhexanoate, Ph3P, acetone. Triethyl phosphite could be used as the ligand for palladium. 

R = NO) with triethyl phosphite is in agreement with these results. 

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