Phosphorochloridate

CopyriQlmSi 1999 John Wile/ Sons Relieved horn vMrw.knovel.QDin 

Handling, Storage, and Precautions highly toxic, corrosive. Use in a fume hood. 

Phosphorylation. Diethyl phosphorochloridate is highly electrophilic and can be cleanly reacted at an anionic center provided that prior metalation is regio- and chemoselective. For example, phenols, thiophenols, and anilines can be phosphorylated under basic conditions (eq 1). The phosphorylated compound can be isolated, or treated further with bases, resulting in orthomet-alation followed by a facile 1,3-phosphorus migration from the heteroatom to carbon. If carbon phosphorylation is desired, simply treating thiophenol with 2 equiv of n-Butyllithium followed by diethyl phosphorochloridate gave a moderate yield (58%).  

Phosphorylation of substituted 1,4-dihydropyridine dianions oeeurred selectively (eq 3). Other reports documented selective phosphorylation at C-5 of thiophenes and the ortho position 

P-Ketophosphonates are valuable intermediates in the realm of Homer-Emmons alkenation methodology. Acyclic variants are difficult to obtain from enol phosphates due to competing alkyne and allene formation. One solution utilized the dianion derived from a-bromo ketones and trapping with diethyl phosphorochloridate however, only moderate yields of P-keto phosphonates were reported. The most efficient procedure utilizes the anion derived from dialkyl methylphosphonate, addition to an aldehyde, followed by oxidation (eq 8).  

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The chlorination of dialkyl phosphonates provides a convenient synthesis of phosphorochloridates ... 

Diethyl chlorophosphate Phosphorochloridic acid, diethyl ester (3,9) (814-49-3)... 

A mixture of 56.8 g (0.21 mol) of diphenyl phosphorochloridate (Note 1), 16.3 g (0.25 mol) of sodium azide, and 300 mL of anhydrous acetone (Note 2) in a 500-mL round-bottomed flask fitted with a calcium chloride tube is stirred at 20-25°C for 21 hr. The lachrymatory mixture is filtered in a hood, and the filtrate is concentrated under reduced pressure. The residue is distilled through a short Vigreux column (Note 3). The yield of diphenyl phos-phorazidate, bp 134-136 C (0.2 ram), is 49-52 g (84-89 ) (Note 4). 

Diphenyl phosphorochloridate (diphenyl chiorophosphate), from Aldrich Chemical Company, Inc., was used after purification by distillation at 165-168 C (5 mm). 

Diphenyl phosphorochloridate Diphenyl chlorophosphate Phosphorochloridic acid, diphenyl ester (8,9) (2524-64-3)... 

Difluoroalkylphosphonates, prepared from difluoroaliylic allcoxides and diethyl phosphorochloridate, are remarkably stable [78] (equation 65). 

Water hydrolyzes diethyl phosphorochloridate [chloro-diethoxyphosphorus(V) oxide] readily but does not affect the diene. Alternatively, the reaction mixture can be processed by fractionation. Evaporation of the petroleum ether and fractionation of the residue through a 25-cm. x 2.2-cm. column of glass helices yields 170 g. (98.5%) of diethyl phosphorochloridate, b.p. 34-36°/0.2 mm., d 1.4210-1.4250 (the refractive index indicates that it contains 5-10% of the title compound), and 240-255 g. (90-96%) of l,2,3,4,5-pentachloro-5-ethylcyclo-pentadiene, b.p. 51-53°/0.2 mm., 1.5398. 

The reaction mixture can also be processed by chromatography. The crude reaction mixture is poured on a 90-cm. x 4.5-cm. column of alumina (e.g, Fisher adsorption grade ) and eluted with about 2 1. of technical-grade pentane. This yields a pale-yellow solution that is free of diethyl phosphorochloridate. Evaporation of the pentane gives 240-255 g. (90-96%) of l,2,3,4,5-pentachloro-5-ethylcyclopentadiene. 

A glyceryl 2-aminoethylphosphonolipid has been isolated from Tetrahymenapyriformis and (45) has been detected by g.l.c.-mass spectrometry in both the lipid and proteinaceous fractions of human brain. The zwitterionic (45) was converted into volatile (46) by acetylation and methylation. Phosphonolipids derived from A-methyl-(45) have been synthesised by acetylation of A-methyl-(45) and subsequent conversion to the phosphorochloridate for the phosphorylation step. °... 

G.l.c. studies of tributylphosphine, dialkyl phosphites, and dialkyl alkylphosphonates are reported. Tributyl phosphate in nitric acid can be estimated by g.l.c. if a glass column is used. Tetraethyl pyrophosphate has been directly determined on a nanogram scale by g.l.c., whereas it was found most convenient to first convert the tetra-aryl pyrophosphates by methanolysis to diarylmethyl phosphates. Phosphorochloridates were converted by t-butyl alcohol into t-butyl chloride before analysis. G.l.c. studies of pesticides have been reported and the isomeric thiophosphates (138a) and (138b) have quite different retention times. ... 

Chlorodiphenylphosphine 488 reacts with a-sulphinyl carbanions to give a-sulphinylphosphines 489 which undergo ready isomerization to a-sulphenylphosphine oxides 4W (equation 295). The report of Almog and Weissman that a-sulphinyl carbanions react with phosphorochloridates 491 to give a-phosphoryl sulphoxides 492 calls for correction (equation 296). Actually, the phosphorylation occurs at the oxygen atom of the ambident dimsyl anion, and is followed by the Pummerer-type reaction affording diethylphosphoric acid and tetraethyl pyrophosphate among other products . ... 

Poly(methyl 3-(l-oxypyridinyl)siloxane) was synthesized and shown to have catalytic activity in transacylation reactions of carboxylic and phosphoric acid derivatives. 3-(Methyldichlorosilyl)pyridine (1) was made by metallation of 3-bromopyridine with n-BuLi followed by reaction with excess MeSiCl3. 1 was hydrolyzed in aqueous ammonia to give hydroxyl terminated poly(methyl 3-pyridinylsiloxane) (2) which was end-blocked to polymer 3 with (Me3Si)2NH and Me3SiCl. Polymer 3 was N-oxidized with m-ClC6H4C03H to give 4. Species 1-4 were characterized by IR and H NMR spectra. MS of 1 and thermal analysis (DSC and TGA) of 2-4 are discussed. 3-(Trimethylsilyl)-pyridine 1-oxide (6), l,3-dimethyl-l,3-bis-3-(l-oxypyridinyl) disiloxane (7) and 4 were effective catalysts for conversion of benzoyl chloride to benzoic anhydride in CH2Cl2/aqueous NaHCC>3 suspensions and for hydrolysis of diphenyl phosphorochloridate in aqueous NaHCC>3. The latter had a ti/2 of less than 10 min at 23°C. 

Hydrolysis of diphenyl phosphorochloridate (DPPC) in 2.0 M aqueous sodium carbonate is also believed to be a two-phase process. DPPC is quite insoluble in water and forms an insoluble second phase at the concentration employed (i.e. 0.10 M). It seems highly significant that the hydrophobic silicon-substituted pyridine 1-oxides (4,6,7) are much more effective catalysts than hydrophilic 8 and 9. In fact, 4 is clearly the most effective catalyst we have examined for this reaction (ti/2 < 10 min). Since derivatives of phosphoric acids are known to undergo substitution reactions via nucleophilic addition-elimination sequences 1201 (Equation 5), we believe that the initial step in hydrolysis of DPPC occurs in the organic phase. Moreover, the... 

Acetohydroximoyl Fluoride, 2,2-Difluoro-2-nitro-, Ethyl Phosphorochloridate C01-C108... 

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