Phosphorous acid phosphoryl phosphite

Considerable interest has been directed to the preparation of cellulose phosphates because of their flame retarding properties and potential use in textiles. Phosphorylation can be accomplished in several ways, e.g., by heating cellulose at high temperatures with molten urea and phosphoric acid. Other phosphor-containing esters of cellulose include phosphites, phosphinates, and phosphonites. In addition, boric acid esters have been prepared. 

The rate of phosphorylation with the amide of propyleneglycolphos-phorous acid is somewhat higher than with the amide trf ethyleneglycol-phosphorous acid. The treatment erf cellulose with the cyclic dimethyl-amide of propyleneglycolphosphorous add produced intermediate cel-lulofe phosphites with a phosphorus content of up to 16% (DS = 1.92). 

Titanium tetrachloride is an efficient reagent for the conversion of trialkyl phosphites and dialkyl hydrogen phosphonates into dialkyl phosphorochloridates. Imidazolides and dialkyl or diaryl phosphoric acids react with acyl fluorides - benzoyl fluoride and oxalyl difluoride being the reagents of choice - to give quantitative yields of the phosphoryl fluorides. The procedure is adaptable to the preparation of fluorides of carbohydrate phosphates in this field, the reaction between the ceu bohydrate and tris-l//-imidazolylphosphine oxide or sulphide with the replacement of one imidazole... 

Examples of the synthesis of phosphite and phosphate esters of sugars are included in a review on trivalent phosphorous acids (Scheme 5). The synthesis of an oxyphosphorane has also been reported (Scheme 6). A strategy for regioselective phosphorylation of aldoses in aqueous solution involves reversible attachment of activated diamidophosphate (DAP). The carbonyl addition prod-... 

Depending on the temperature conditions, carbon disulfide can be phosphorylated by sodium dialkyl phosphites either at the carbon or at one of the sulfur atoms. At relatively low temperatures (2-8 °C), the phosphorus-containing xanthate I is obtained [375], whereas at higher temperatures (70-100 °C), the 0,0-diethyl ester of S-thioacetyl-thio-phosphoric acid II is the major product [376]. 

Phosphorylated derivatives are also available. Cellulose pulp or linters can react with phosphoric acid in a urea melt or with a mixture of phosphoric acid and phosphorus pentoxide in an alcoholic medium to prepare cellulose phosphate. Cellulose phosphites and phosphonates are produced via transesterification with alkyl phosphites. All these compounds have fire-retarding properties and ion-exchange properties and cellulose phosphate is used in textile and paper manufacture, as well as in the treatment of kidney stones. 

Phosphorous acid esters from phosphoryl phosphites ... 

---