Phosphorodichloridates alcohols

Phosphorylation of cholesterol followed by the normal hydrolytic work-up gives the phosphate monoester, not the symmetrical pyrophosphate diester as previously claimed. Cholesteryl phosphorodichloridate and some related steroidal phosphorodichloridates have been prepared from the action of pyrophosphoryl chloride on the appropriate alcohol ... 

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. 

Compound Name Ethylhexaldehyde N-Propyl Alcohol Diethyl Carbonate Ethyl Chloracetate Ethyl Chloride Ethyl Chloroacetate Ethyl Chloroformate Ethyl Chloroacetate Ethyl Chloroacetate Ethyl Phosphorodichloridate Ethyldichlorosilane Ethylene... 

As already known, a halogen atom at position 4 in the pyridazine ring is more reactive towards nucleophiles then one at position 3. This has been confirmed also with 3,4-dichloro-5,6-diphenylpyridazine and various nucleophiles (81MI2). The high reactivity of 6-halo-1,3-dimethylpyridaz-inium halides or phosphorodichloridates has been used to prepare alkyl halides from alcohols (80S746). 

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... 

The phenyl ether was obtained similarly. The Sa-saturated 3 -ol affords its methyl ether, but not the phenyl ether, under these conditions. The conversion of sterols into their phosphorodichloridates, and the reactions of these with amines and alcohols, have been studied. 

I, 2-0-Isopropylidene-a-D-xylo- and -ribo-furanose each gave the two possible isomers of the corresponding cyclic 3,5-(phenyl phosphate) when treated with phenyl phosphorodichloridate, but only one isomer was formed on phosphorylation of the former compound with bis-(2,2,2-trichloroethyl) phosphorochlori-date. The synthesis of a new type of branched-chain sugar phosphate, trans-3-C-cyanomethylene-3-deoxy-l,2-0-isopropylidene-a-D-erythro-pentofuranose 5-[bis-(2,2,2-trichloroethyl) phosphate], was also reported. 2,3,4,6-Tetra-0-acetyl(or benzoyl)-P-D-glucopyranose reacted with tris(dimethylamino)phosphine and carbon tetrachloride to give both anomeric oxyphosphonium chlorides (see Vol. 9, p. 48), which afforded 1,2-orthoesters with alcohols or a mixture of phenyl 1-thio-D-glucopyranosides with thiophenol. Similar treatment of 2,3,4,6-tetra-... 

Sodium alcohol Phosphoric acid esters from phosphorodichloridates... 

Phosphorylation. Phosphorus oxychloride reacts with alcohols, amines, and thiols, resulting in phosphorylation of these functional groups. Trimethyl phosphate is a particularly effective solvent, and tertiary amine bases are generally used as well. Treatment of primary alcohols with POCI3 results in the formation of phosphonyl dichloride intermediates which, in the presence of excess alcohol, convert to symmetrical trialkyl phosphates. It is generally possible to isolate aryl phosphorodichloridates when a two-fold excess of (1) is used and AICI3, KCl, or pyridine is used as a catalyst. Secondary and tertiary alcohols tend to form alkyl chlorides and phosphoric acid. 

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