Ethyl dichlorophosphite

A convenient synthesis of uridine 2, 3 -cyclic phosphite 15 (as a 3 4 mixture of diasteroisomers because of the chirality at phosphorus) was based on the reaction of the suitably protected uridine derivative 14 with ethyl dichlorophosphite carried out in the presence of triethylamine and anhydrous ethanol (Scheme 6) [21]. After adding ethanol into the reaction medium, an efficient chromatographic separation of the crude reaction product was achieved on silica gel with diethyl ether giving analytically pure phosphite 15 in 75% yield. It is interesting to note that without adding ethanol, 15 is very unstable. 

Ethoxy-l,3,2-oxazaphospholidine 59 was prepared as a single diastereomer from (-)ephedrine (42) and ethyl dichlorophosphite 57. Its Arbusov reaction with allyl bromide gave the corresponding allyl phosphonates 61a,b as a diastereomeric mixture which could be separated by flash column chromatography and crystallization (Scheme 21) [48], On applying a similar protocol, starting from... 

A rich family of 2-alkoxycarbonyl-l,3,2-oxazaphospholidine-2-oxides 179-181 was prepared from the reaction of camphor derived aminoalcohols 177 and 178 with either methoxycarbonyl phosphonic dichloride or ethyl dichlorophosphite followed by the reaction with methyl bromoacetate. The reaction with aminoalcohol 177a afforded the phosphorus epimers 179 and 180, in ratios from 1/1 to 12/1 depending on the iV-substituent which could be separated easily by column chromatography. The reaction with aminoalcohols 178a-c, however, gave a single epimer 181a-c in each case (Scheme 50) [81]. 

The same paper [19] reports on the phosphorylation of 5-bromoisatin o-carboxyphenylhydrazone hydrochloride by ethyl dichlorophosphite, resulting in the synthesis (according to the author) of 3-[N-(2-alkoxy-6-oxobenzo[J]-l,3,2-oxoazophosphorin-3-yl)imino]isatin (54) ... 

Ethyl dichlorophosphite and methyl dichlorophosphite have been prepared by the reaction of 1 mol of the appropriate alcohol with 1 mol of phosphorus(III) chloride.1 The ethyl compound has also been prepared from triethyl phosphite and phosphorus(III) chloride.2 The method outlined below is essentially the former however, several improvements have been incorporated. Among the difficulties encountered in the preparation of these compounds are the following Side reactions occur between the generated hydrogen chloride and the ester, giving an alkyl chloride and phosphorous acid disproportionation may occur in the case of the ethyl ester, the necessary vacuum distillation causes losses of the relatively low boiling product. 

Central Research Department, Monsanto Chemical Company, Dayton, Ohio. (This author worked with ethyl dichlorophosphite.)... 

Ethyl dichlorophosphite is a colorless liquid, with an irritating odor. It fumes when exposed to air. It has the following physical constants sp. gr., 1.30526 b.p., 117.5° n °, 1.47176. It decomposes at 165° to ethyl chloride, phosphorus, phosphine, and phosphoric acid.3 It reacts with water to form hydrogen chloride and phosphorous acid, and with alcohols to form esters. When ammonia is passed through ethyl dichlorophosphite, ethyl phospheni-midate (ethoxyphosphimide), C2H5OP=NH, is formed. 

Special solvent. Diethyl phosphonate is miscible with water and with ordinary organic solvents and has remarkable solvent power. It is recommended as solvent and acid-acceptor for peptide syntheses utilizing tetraethyl pyrophosphite" or a reagent such as ethyl dichlorophosphite. ... 

Trimethylsilyl)ethanol has been used as a protecting group in phosphate monoester synthesis and involves the use of 2-(lrimethylsilyl)ethyl dichlorophosphite (eq 14). Bis[2-(trimethylsilyl)ethyl] (V,(V-diisopropylphosphoramidite has been prepared from dichloro(diisopropylamino)phosphine and 2-(trimethylsilyl) ethanol and used as a phosphitylating agent in the synthesis of phosphotyrosine containing peptides (eq 15). ... 

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