By means of phosphites

Like tertiary phosphines, trialkyl phosphites can be alkylated by quaternary salts or hydrohalides of Mannich bases, this reaction widening the applicability of the Michaelis-Arbuzov reaction (cf. page 725) analogous alkylation of sodium dialkyl phosphites (cf. page 728) gives poorer yields of phosphonic esters.354,355 

Diethyl (3-oxobutyl)phosphonate 354 The methiodide obtained from 4-(diethylamino)-2-butanone (7.15 g, 0.05 mole) and methyl iodide (7.15 g) is heated with triethyl phosphite (0.25 mole, 41.5 g) for 1 h at 130°. After cooling, the triethylmethylammonium iodide formed (10.6 g, 87%) is filtered off and washed with benzene. On evaporation the filtrate and wash-benzene leave a pale yellow oil which is distilled in a vacuum (yield 8.4 g, 81 % b.p. 89-97°/ 0.08 mm) and on redistillation gives the phosphonic ester (7.5 g, 72%), b.p. 96-98°/0.14 mm, nD25 1.4352. 

The preparation of -amino phosphonic esters from aminals and dialkyl phosphites was mentioned above (page 732) tetraalkyl pyrophosphites and aminals also yield oc-amino phosphonic esters as well as amino phosphites.356 

The most convenient method of preparing (chloro)diphenylphosphine is by disproportionation of the readily accessible dichloro(phenyl)phosphine  

Yields of 70-80% are achieved by adding catalytic amounts of aluminum chloride and continuously distilling off the phosphorus trichloride.357-359 

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Replacement of oxygen by phosphorus by means of phosphites and related... 

Examples of the intermolecular C-P bond formation by means of radical phosphonation and phosphination have been achieved by reaction of aryl halides with trialkyl phosphites and chlorodiphenylphosphine, respectively, in the presence of (TMSlsSiH under standard radical conditions. The phosphonation reaction (Reaction 71) worked well either under UV irradiation at room temperature or in refluxing toluene. The radical phosphina-tion (Reaction 72) required pyridine in boiling benzene for 20 h. Phosphinated products were handled as phosphine sulfides. Scheme 15 shows the reaction mechanism for the phosphination procedure that involves in situ formation of tetraphenylbiphosphine. This approach has also been extended to the phosphination of alkyl halides and sequential radical cyclization/phosphination reaction. ... 

Infrared measurement of additive concentrations is a more complex analysis than initially expected, as some additives may undergo a variety of chemical reactions during processing, as shown by Reeder et al. [128] for the FTIR analysis of phosphites in polyolefins. Some further examples of IR work refer to PVC/metal stearates [129], and PE/Santonox R [68,130]. Klingbeil [131] has examined the decomposition of various organic peroxyesters (TBPB, TBPP, TBPA and TBPO) and a peroxidicarbonate (BOPD) as a function of pressure, temperature and solvent by means of quantitative FTIR using an optical high p, T reaction cell. 

On-line SFE-pSFC-FTIR was used to identify extractable components (additives and monomers) from a variety of nylons [392]. SFE-SFC-FID with 100% C02 and methanol-modified scC02 were used to quantitate the amount of residual caprolactam in a PA6/PA6.6 copolymer. Similarly, the more permeable PS showed various additives (Irganox 1076, phosphite AO, stearic acid - ex Zn-stearate - and mineral oil as a melt flow controller) and low-MW linear and cyclic oligomers in relatively mild SCF extraction conditions [392]. Also, antioxidants in PE have been analysed by means of coupling of SFE-SFC with IR detection [121]. Yang [393] has described SFE-SFC-FTIR for the analysis of polar compounds deposited on polymeric matrices, whereas Ikushima et al. [394] monitored the extraction of higher fatty acid esters. Despite the expectations, SFE-SFC-FTIR hyphenation in on-line additive analysis of polymers has not found widespread industrial use. While applications of SFC-FTIR and SFC-MS to the analysis of additives in polymeric matrices are not abundant, these techniques find wide application in the analysis of food and natural product components [395]. 

Nagoumey and Madan [20] have considered both AAS and ICP-AES as reliable measurement techniques for the determination of metal components in mixed-metal/phosphite stabiliser systems in PVC. For reasons given elsewhere (Section 8.3.2.4), in this case ICP-AES was considered the technique of choice for most metal stabiliser determinations, while AAS remains a useful method to corroborate the ICP-AES results. For the determination of tin in rigid PVC by means of HG-AAS, the main effort has been to develop a sample digestion procedure [118]. Tin and Ti from a PVC potable... 

Sekine, M., Mori, H., and Hata, T., Protection of phosphonate function by means of ethoxycarbonyl group. A new method for generation of reactive silyl phosphite intermediates, Bull. Chem. Soc. Jpn., 55, 239, 1982. 

B. 2-Phenylindazole. In a 200-ml. round-bottomed flask fitted with a condenser are mixed 50 g. (0.30 mole) of triethyl phosphite (Note 5) and 22.6 g. (0.10 mole) of o-nitrobenzalaniline. The apparatus is sealed from the atmosphere by means of a liquid... 

As previously stated (p. 53) di-(2-chloroethyl) phosphoro-fluoridate can be prepared by the action of phosphorus oxydi-chlorofluoride on ethylene chlorohydrin. The compound can also be prepared by the fluorination of di (2-chloroethyl) phos-phorochloridate, prepared from di-(2-chloroethyl) hydrogen phosphite (XVIII), obtained by the action of phosphorus trichloride on ethylene chlorohydrin. This partial fluorination was effected by means of sodium fluoride, although the yield was not high. The chlorine atoms of the 2-chloroethyl groups were not affected by this procedure, a fact which falls into line with the observations of Saunders and Stacey (p. 12) that ethylene chlorohydrin is not readily fluorinated by sodium fluoride, but only by potassium fluoride under pressure in a rotating autoclave.1... 

Table 6.5 Polycondensation of various amino acids by means of triphenyl phosphite in the presence of PVP. [Reprinted from N. Yamazaki and F. Higashi, Adv. Polym. Sci., 38, 1 (1981)1...

The cyclization of 1,5-dicarbonyl chains by means of the deoxygenating reagent triethyl phosphite provides an alternate strategy for building the fused hve-membered penem ring. The first example in fact actually comprises a 1,5-oxa-thio array. Reaction of the perhydrothiophene oxide (16-1) with the anion from carbon disulhde... 

Iodoallenes are prepared from propargyl alcohols by means of phosphonium iodide produced in situ from triphenyl phosphite and methyl iodide. In addition, small amounts of the isomeric iodoacetylenes are formed in this process. 

Fourth, the present procedure bears a resemblance to the photochemical reaction of aryl iodides with trialkyl phosphites, by means of which several dialkyl arylphosphonates have been prepared.13 However, prolonged irradiation (>24 hours) in quartz vessels was employed. 

To obtain more information on the nature of the quasiphosphonium intermediates involved in these systems we have studied the reactions gf sterically hindered neopentyl esters by means of 1P nmr spectroscopy. Trineopentyl phosphite and a-bromoacetophenone gave rise to a peak at +41 ppm due to the ketophosphonium intermediate 3 (R = Me.CCH, R = Ph X = Br ) within half an hour of mixingJthe reactants in acetone-dfi at 27 °C ( p nmr shifts are relative to 85% H-PO. down-field positive). Peaks due to the ketophospnonate 4 +19 ppm and the vinyl phosphate 7 (-7 ppm) were also observed (compound 4 and 7 have satisfactory elemental analysis and spectroscopic data ). The concentration of the intermediate reached a maximum after about two hours when it was precipitated from acetone solution by the addition of anhydrous ether to give white crystals of trineopentyloxy (phenacyl)phosphonium bromide, identified by elemental analysis and nmr spectroscopy ( XP 6+41, in CDCl ). When redissolved in acetone-dg, deuterochloroform, acetic acid, or acetic acid-acetone mixtures, the intermediate decomposed to yield keto-phosphonate 4 but none of the vinyl phosphate 6 (Perkow product). Nor was the course of reaction affected by the addition of chloride ion or of a-chloro-acetophenone in acetonitrile. 

Because the phosphonate-phosphate rearrangement requires P-C bond breakage and formation of the P-O bond kinetic isotope studies by means of 13C NMR were chosen.50 13C KIEs were derived from NMR analysis of substrate-o-nitro-benzaldehyde or product-phosphate. Samples of aldehyde were prepared using the dead-end method. To the solution of phosphite 3 and triethylamine in acetonitrile an excess of aldehyde was added and solution was heated at 65°C to complete conversion of phosphonate 4 to phosphate 5 monitored by 31P NMR. The aldehyde conversions 0.2-0.8 were calculated from the balance of concentrations. The changes of 13C composition were determined for carbonyl carbon atom using signal of meta aryl carbon as an internal standard. KIE 1.0223(14) was calculated from the slope of linear relationship of isotopic ratio R and fraction of reaction,... 

Azole approach. Application of the commonly used method for reductive cyclization of aromatic nitro compounds by means of triethyl phosphite to the 4-c-nitrobenzylidene oxazoles (249) leads to the fused quinolines (250) (69JCS(C)385). 

Disconnect the gas inlet tube from the flask containing the phosphite-ozone adduct and replace it by a rubber septum. Connect the two flasks by a cannula and, while maintaining both at -78°C under nitrogen, add dropwise by means of applying a positive pressure of nitrogen, the phosphite-ozone solution through the cannula to the stirred solution of the ylide 89 over a period of 50 min. Maintain the mixture at -78°C for 1 h and then allow it to warm to room temperature. 

Peptide synthesis. Japanese chemists have reported a convenient synthesis of peptides by means of diphenyl phosphite and a tertiary amine (pyridine was used) as summarized in the equation. Various peptides were prepared in this way in high yield... 

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