Triethyl phosphite, preparation

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%. 

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. 

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

More recently, a double reductive ring closure of the dinitrodiphenylbenzene 139 with triethyl phosphite as the reducing agent has been reported to produce 3 in 59% yield (Scheme 18). The precursor 139 was prepared in excellent yield by Pd(0)-catalyzed coupHng of phenylboronic acid and 1,3-dibromo-4,6-dinitro-benzene (92JHC1237). 

The free acid analogue of the antipsoriatic agent etretinate (103) is prepared in substantially the same way as the parent compound. Thus, the aldehyde group in 98 is converted finally to the pho.sphonate (101) by sequential reduction (99), conversion to the chloride (100), and finally reaction with triethyl phosphite. Condensation of the ylide from 101 with the benzaldehyde 102 gives etretinate (103) saponification affords acitretin (104) [25]. 

Whereas the production of arylnitrenes by the deoxygenation of nitrosobenzenes or nitro-benzenes by trivalent phosphorus reagents and their subsequent intramolecular ring expansion to 3//-azepines are well-known processes, the corresponding intermolecular reactions to form 1//-azepines have been exploited only on rare occasions and appear to be of little preparative value. For example, the highly electrophilic pentafluorophenylnitrene, obtained by deoxygenation of pentafluoronitrosobenzene with triethyl phosphite in benzene solution, produced a low yield (2-10%) of l-(pentafluorophenyl)-l//-azepine, which was isolated as its [4 + 2] cycloadduct with ethenetetracarbonitrile.169 With anisole as the substrate l-(pentafluorophenyl)-l//-azepin-2(3//)-one (16% bp 128 —130 C/0.4 Torr) was obtained. 

Phosphorous derivatives of fatty acids were also prepared by heating acyl chlorides, bromoethyl esters, or vinylbromo esters with triethyl phosphite in an Arbusov reaction [88-90] see Eqs. (42)-(44) ... 

A simple, high-yield procedure for the conversion of ArTlXj into ArjTlX compounds has recently been described 90). This symmetrization reaction, the mechanism of which is not known, can be effected by treatment of the ArTlX2 compound either with triethyl phosphite or with hot aqueous acetone. As a wide variety of ArTlXj compounds can now be easily prepared by electrophilic thallation of aromatic substrates with thallium(III) trifluoroacetate (q. v.), symmetrization represents the method of choice for the preparation of the majority of ArjTlX compounds. Only about twenty mixed compounds, RR TIX, have been prepared so far, and the only general synthetic procedure available consists of a disproportionation reaction between an RTIX2 species and another organometallic reagent [e.g., Eqs. (5)-(7)]. 

A useful approach for the preparation of chiral (3-aminophospho-nic acids from the naturally occurring a-amino acids has been reported.139 The overall scheme (Equation 3.4) involves formation of the phthalimide-acid halide from the starting a-amino acid followed by a Michaelis-Arbuzov reaction with triethyl phosphite to give the acylphosphonate. Complete reduction of the carbonyl group in three steps followed by hydrolysis of the ester and amide linkages provides the target material in very high yield without racemization (>99% ee). 

Triethyl phosphonoformate was prepared by the dropwise addition of ethyl chloroformate (10.85 g, 0.1 mol) to triethyl phosphite (16.6 g, 0.1 mol) with vigorous stirring at ambient temperature. After the... 

To a solution of the titanocene(II) reagent 29 in THF (42 mL) in a 300-mL round-bottomed flask, prepared from titanocene dichloride (6.54 g, 26.3 mmol), magnesium turnings (0.766 g, 31.5 mmol), triethyl phosphite (8.96 mL, 52.5 mmol), and finely powdered 4 A molecular sieves (1.31 g) according to the procedure described above, was added a solution of l,l-bis(phenylthio)cyclobutane (63 2.29 g, 8.40 mmol) in THF (14 mL). The reaction mixture was stirred for 15 min. and then a solution of (S)-isopropyl 3-phenylpro-panethioate (91 1.46 g, 7.00 mmol) in THF (21 mL) was injected dropwise over a period of 10 min. The reaction mixture was refluxed for 1 h, then cooled, whereupon 1 m aq. NaOH solution (150 mL) was added. The insoluble materials produced were removed by filtration through Celite and washed with diethyl ether. The aqueous layer was separated and extracted with diethyl ether. The combined ethereal extracts were dried (Na2S04), filtered, and concentrated. The residual liquid was purified by column chromatography (silica gel, hexane) to afford 1.33 g (77%) of (l-isopropylthio-3-phenylpropan-1 -ylidene) cyclobutane (92). 

Scheme 2 shows preparation of the biftinctional fiber. PPPE-c and PPPE-f grafted with CMS and ST were functionalized by the reported method.6 Here, an example of functionalization procedures is described. The precursory fibers (PPPE-f grafted with CMS and ST, 2 g) and triethyl phosphite (60 ml) were taken into a three-necked flask (200 ml) equipped with a Liebig condenser. After the mixture in the flask was heated for 48 h at 100 °C, the resulting phosphorylated PPPE-f was washed with acetone, aceton-water mixture and water, and dried in vacuum oven at 40 °C. In order to introduce sulfonic acid groups, the phosphorylated PPPE-f was treated with a 30 mL of 1,2-dichloroethane solution of chlorosulfonic acid (10 wt %) for 2 h at room temperature. Finally, diethyl phosphonate groups on the fibers were hydrolyzed with 12 M hydrochloric acid under refluxed... 

An Arbuzov reaction of triethyl phosphite with A-chloroamines RNHC1 (R = i-Pr, cyclohexyl or PhCH2), prepared from the corresponding amines and aqueous sodium hypochlorite, leads to the phosphoramides 357 with the elimination of ethyl chloride395. 

A flask is charged with finely powdered molecular sieves (4 A, 50 mg), magnesium turnings (97 mg, 4.0 mmol), titanocene dichloride (249 mg, 1.0 mmol), THE (5 mL), triethyl phosphite (0.34 mL, 326 mg, 2.0 mmol) and 1-octene (224 mg, 2.0 mmol), in the order given. The resulting mixture is stirred for 2 h at room temperature and a solution of 2 [( )-2-phenylethenyl]-l,3-dithiane (111 mg, 0.5 mmol) in THF (2 mL) is added. The mixture is stirred for 4 h and then diluted with hexane (30 mL). Filtration through Celite, concentration of the filtrate, and purification of the product by preparative TLC gives 82 mg (72%) of the title compound as a mixture of cis and trans cyclopropanes (cis/trans 60 40). 

Isomeric l,3a,4,6a- (220) and l,3a,6,6a- (91) dibenzotetraazapentalenes can be prepared from the thermal decomposition of 2-((9-azidophenyl)-2//-benzotriazole (224) and - o-azidophenyl)-2//-benzotriazole (230), respectively, in high boiling solvents such as 0-dichlorobenzene and decalin. This synthesis was improved upon when it was found that (220) and (91) can be prepared from the reactions of 2-((9-nitrophenyl)-2//-benzotriazole (226) and l-(o-nitrophenyl)-2//-benzotriazole (229), respectively, with triethyl phosphite in refluxing xylene. ... 

Ethyl fluorophosphonate is commercially available it is prepared through a Michael-Arbuzov reaction between triethyl phosphite and ethyl bromofluoroacetate. 

Sugars containing a carbon-phosphorus bond have been prepared by application of the Michaelis-Arbuzov reaction to bromodeoxy sugars. Thus, the reaction of 5-bromo-5-deoxy-l,2-0-isopropylidene-3-O-methyl-a-D-xylofuranose (131) with triethyl phosphite yields the corresponding diethyl phosphonate (132) compound 132 was employed for the synthesis of a sugar derivative having phosphorus as... 

---