Phosphorochloridates Phosphorodichloridates

Imidocarbonyl Chloride Fluoride, Hydroxy-, Phosphorodibromidate Imidocarbonyl Chloride Fluoride, Hydroxy-, Phosphorodichloridate Imidocarbonyl Chloride, Hydroxy-, Methyl Phosphorochloridate Imidocarbonyl Chloride, Hydroxy-, Phosphorodichloridate Imidocarbonyl Fluoride, Hydroxy-, Ethyl Phosphorochloridate Imidocarbonyl Fluoride, Hydroxy-, Methyl Phosphorochloridate Imidocarbonyl Fluoride, Hydroxy-, Phosphorodichloridate Iminodiethanol Imochi Imochi-byo... 

The disadvantage of this method, especially for large-scale work, lies in the utilization of large quantities of pyridine. Furthermore, with ethyl alcohol some ethyl phosphorodichloridate (II) is usually produced even under conditions favourable to the production of diethyl phosphorochloridate. 

Phosphorus oxychloride is a suitable reagent for preparation of the symmetrically substituted phospho-triesters of type (RO)3PO. The preparation is easily achieved by treatment of phosphorus oxychloride with 3 equiv. of alcohols or their metal salts. The reaction is generally promoted by a base or acid. Titanium trichloride is a particularly effective catalyst for the reaction. Conversion of POCI3 to unsymmetri-cally substituted phosphotriesters is achievable with difficulty. Phosphorochloridates and phosphorodichloridates have been used for the preparation of mixed tertiary phosphoric esters of type (ROlmPOfOROn (ffi = 1, n = 2, or m = 2, n = 1) in a very wide variety. Reaction of phosphorus oxychloride and 1 or 2 equiv. of alcohols followed by hydrolysis forms phosphomonoesters or phosphodi-esters, respectively. The hydrolysis may be generally effected by dilute aqueous alkali. Some phosphoFodichlori te intermediates are easily hydrolyzed by water. For example, the phosphorylation of a ribonucleoside (1 equation 4) with phosphorus oxychloride in an aqueous pyridine-acetonitrile mixture furnishes the nucleoside S -monophosphate (2) in excellent yield. ... 

On reaction with alcohols, these compounds give alkyl phosphorodichloridates and alkyl thiophosphorodichloridates, respectively, which can be converted with a second mole of alcohol in the presence of an acid-binding base to dialkyl phosphorochloridate and its thio analogues (Fletcher et al., 1948 Melnikov et at., 1959). 

Polyfluoroalkyl phosphorodichloridates and bis(poly-fluoroalkyl) phosphorochloridates have been prepared from the corresponding alcohols. The reactions between polychloro-1-nitrosoethanes and phosphorus(III) chlorides have provided the phosphoryl chlorides (3) and (4) whilst the same procedure... 

At 600 °C in the vapour phase the aryl phosphorodichloridate (39) cyclizes to (40). The reaction of dimethyl phosphorochloridate with aniline in nitrobenzene appears to be catalysed by both the reactants and the products. When the phosphorimidic chloride (41) was treated with... 

Although the phosphorochloridic acids are, in principle, related as in (5.263), they are more difficult to isolate than their fluoro analogues. Phosphorodichloridic acid can be prepared by the hydrolysis of pyrophosphoryl chloride at -60°C (5.279) or from phosphoryl chloride and water (5.280). It is a clear liquid, stable in the absence of air and has a melting point of -18°C. 

Several other compounds are formed in the reaction such as diesters (R0)2P02H, triesters (RO)3PO and cyclic esters. In order to avoid these side reactions, substituted compounds are now used, particularly diphenyl phosphorochloridate [(CjH50)2POCl], dibenzyl phosphorochloridate [(CfiH.CHiOliPOCllformonoesters, and phenyl phosphorodichloridate (C6HjO-POCl2) for diesters. 

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