Vinylphosphonates

Organophosphorus Monomers. Many vinyl monomers containing phosphoms have been described in the Hterature (76), but few have gone beyond the laboratory. Bis(2-chloroethyl) vinylphosphonate [115-98-0] C H Cl O P, is a commercially available monomer (Akzo s Fyrol Bis-Beta) made from bis(2-chloroethyl) 2-chloroethylphosphonate. 

Several appHcations have been found for bis(2-chloroethyl) vinylphosphonate as a comonomer imparting flame retardancy for textiles and specialty wood and paper appHcations. Its copolymerization characteristics have been reviewed (76,109). This monomer can be hydrolyzed by concentrated hydrochloric acid to vinylphosphonic acid, polymers of which have photoHthographic plate coating utiHty (see Lithography). It is also an intermediate for the preparation of an oligomeric vinylphosphonate textile finish, Akzo s Fyrol 76 [41222-33-7] (110). 

Oligomeric Vinylphosphonate. A water-soluble oligomer, Fyrol 76 [41222-33-7] is produced by reaction of bis(2-chloroethyl) vinylphosphonate and dimethyl methylphosphonate with elimination of all the chlorine as methyl chloride (127,128). This Hquid, containing 22.5% P, is curable by free-radical initiation, on cotton or other fabrics. Nitrogen components, such as A/-methylolacrylamide or methylolmelamines, are usually included in the finish, which can be durable to multiple launderings (129,130). 

Fluoroalkanephosphonic acid can be obtained by addition of iodine perfluoroalkane to vinylphosphonic acid dichloride followed by saponification and deiodination by sodium amalgam [141]. Fluoroalkanephosphonic acids can be transformed to fluoroalkanephosphonic acid glycil esters by 2 mol of epi-chlorhydrin in a water-free solution followed by reaction with alkalines or amines [142]. Compounds of this kind with an alkyl chain of 8-20 carbon at-... 

The pyrazole analog 140 has been prepared from the reaction of the alkynyl phosphonate with ethyl diazoacetate, whereas the pyrazoline 139 was obtained under similar conditions with diediyl vinylphosphonate (78). 

The optically active a-sulfinyl vinylphosphonate 122 prepared in two different ways (Scheme 38) is an interesting reagent for asymmetric synthesis [80]. This substrate is an asymmetric dienophile and Michael acceptor [80a]. In the Diels-Alder reaction with cyclopentadiene leading to 123, the endo/exo selectivity and the asymmetry induced by the sulfinyl group have been examined in various experimental conditions. The influence of Lewis acid catalysts (which also increase the dienophilic reactivity) appears to be important. The 1,4-addition of ethanethiol gives 124 with a moderate diastereoselectivity. 

Scheme 36 Preparation of vinylphosphonates via free radical Arbuzov reaction...

Esters of a-diazoalkylphosphonic acids (95) show considerable thermal stability but react with acids, dienophiles, and triphenylphosphine to give the expected products. With olefinic compounds in the presence of copper they give cyclopropane derivatives (96), but with no such compounds present vinylphosphonic esters are formed by 1,2-hydrogen shift, or, when this route is not available, products such as (97) or (98) are formed, resulting from insertion of a carbenoid intermediate into C—C or C—H bonds. The related phosphonyl (and phosphoryl) azides (99) add to electron-rich alkynes to give 1,2,3-triazoles, from which the phosphoryl group is readily removed by hydrolysis. 

Diazoalkanes add readily to the double bond of esters of vinylphosphonic acid, giving the pyrazoline derivatives (100), which can lose nitrogen to give esters of cyclopropylphosphonic acids. In a similar reaction, acyl-phosphonic acid esters (101) were converted to epoxy-derivatives (102). A -Phenylsydnone adds to diethyl prop-l-ynephosphonate, giving the pyra-zole (103). The addition of cyclopentadiene to dimethyl vinyl phosphate leads to an exojendo quotient of 1.2, but with hexachlorocyclopentadiene only e/ii/o-isomer is formed. ... 

Detailed interpretations of the n.m.r. spectra of vinylphosphonic acid," phosphoenolpyruvate, and some TV -phosphorylaziridines have been carried out. The vibrational spectra of ethyl phosphorodichloridate and its 1,1-dideuterio- and 2,2,2-trideuterio-derivatives have been examined. 

Wilson, A. D. Ellis, J. (1989). Poly-vinylphosphonic acid and metal oxide or cermet or glass-ionomer cements. British Patent Application 2, 219, 289A. 

This chapter is devoted to a miscellaneous group of aqueous acid-base cements that do not fit into other categories. There are numerous cements in this group. Although many are of little practical interest, some are of theoretical interest, while others have considerable potential as sustained-release devices and biomedical materials. Deserving of special mention as biomedical materials of the future are the recently invented polyelectrolyte cements based on poly(vinylphosphonic adds), which are related both to the orthophosphoric acid and poly(alkenoic add) cements. 

Ellis and Wilson studied cements formed from concentrated solutions of poly(vinylphosphonic acid) (PVPA) and oxides and silicate glasses, which they termed metal oxide and glass polyphosphonate cements (Wilson ... 

Ellis, J., Anstice, M. Wilson, A. D. (1991). The glass polyphosphonate cement a novel glass-ionomer cement based on poly(vinylphosphonic acid). Clinical Materials, 7, 341-6. 

Rovis and co-workers have also shown that pre-catalyst 129 is competent with a wide range of Michael acceptors including oc,P-unsaturated aldehydes, amides, nitriles, esters, thioesters, vinylphosphonates and vinylphosphine oxides (Scheme 12.25) [58,60],... 

The vinylphosphonic esters (77) are obtainable by distillation of the phosphite esters (76)(Scheme 13). No reaction takes place at the vinyl halogen during the preparation of the esters (78), but the interaction of phosphonites and... 

In contrast with the behaviour of typical vinylphosphonic acid derivatives, the carbon-carbon double bond in the 1,2-oxa-phospholene (167) is remarkably unreactive towards a broad spectrum of reagents including electrophiles, most epoxidizing and organometallic reagents, as well as to dipolar addition reactants. Exceptional reagents are, however, N-bromoacetamide (NBA), ozone, dimethyllithiumcuprate, and sodium-naphthalene. 

P-Bromophosphonic acid 138, a,P-dibromophosphonic acid 139, and 2-bromo-vinyl-l-phosphonic acid 140 are hydrolyzed fast by aqueous sodium carbonate92. Compounds of structure comparable with that of 140 are the vinylphosphonic... 

An interesting reaction was studied by A. Schwartz (1997) UV irradiation of phosphate solutions containing acetylene gave vinylphosphonic acid. 

Fig. 4.11 The assumed mechanism of the synthesis of vinylphosphonic acid via addition of the phosphite radical to acetylene (de Graaf et al., 1997)...

What importance could vinylphosphonic acid have for the synthesis of important biomolecules Its photolysis gives many oxidized products, including phosphoac-etaldehyde. This analogue of glycol aldehyde phosphate seems to be of interest its formation involves the recombination of hydroxyl radicals with vinylphosphonic acid radicals. 

Scheme 21 Synthesis of vinylphosphonates 63a,b and their conversion to diastereomeric phosphonates 64 or 65...

A-trityl-(l/ ,2S)-norephedrine (58), the corresponding allyl phosphonates 62a,b were obtained via the Arbusov rearrangement of 2-ethoxy-1,3,2-oxazaphospholidine 60. The absolute configuration of the major diastereomer, 62a was determined by X-ray as (2S1,45,51 ).The reaction of the major diastereomer of allyl phosphonates 61a and 62a with DBU afforded the corresponding vinylphosphonates 63a,b (Scheme 21) [48], Nucleophilic addition to these resulted in induction of chirality at the [1-position of the stereogenic phosphorus atom in the initially produced diastereomeric phosphonates 64 or 65 (Scheme 21) [48],... 

Andreae, S. and Seeboth, H., Synthesis of 2-furyl- and 5-nitro-2-furyl-sub-stitued vinylphosphonic acids, Collect. Led. Int. Symp. Furan Chem., 3rd Slovak Tech. Univ., Fac. Chem. Technol., Bratislava, Czechoslovakia, 1979, p. 117. 

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