Dimethyl acetylphosphonate

Further studies on 1,3-dipolar addition reactions of diazophosphonates have been recorded,122 and work on 2-diazo-l-hydroxyalkylphosphonates also continues.123 The ester (155 R = H) reacts with esters of acetylenedicarboxylic acid without liberation of nitrogen to give stereoisomeric C-phosphorylated pyrazolines, which can be decomposed with both phosphorus-carbon and carbon-carbon bond fission, affording mixtures containing dimethyl acetylphosphonate, dimethyl hydrogen phosphonate, and tri(alkoxycarbonyl)pyrazolines. In the reaction between the same diazophosphonate and diazomethane, the latter conceivably acts as a basic catalyst for proton transfer in a series of steps which includes phosphonate-phosphate isomerization. The importance of a labile proton is demonstrated by the fact that the ester (155 R = Me) does not react in the manner described above. 

Diazoalkanes are well known as reagents for carbon insertion reactions through the intermediacy of carbenes. Here, diethyl acetylphosphonate has been shown to react with diazomethane to give a mixture of 2-(diethoxyphosphinoyl)-2-methyloxirane (the major product) together with traces of diethyl (2-oxopropyl)phosphonate the reaction between dimethyl acetylphosphonate and diazoethane and that between diethyl ben-zoylphosphonate and diazomethane both afford only the (2-oxoalkyl)phosphonic... 

Dialkyl acylphosphonates are sensitive to water in neutral and alkaline conditions and hydrolyse rapidly to the corresponding carboxylic acids and to dialkyl hydrogen-phosphonate (equation 47) This occurs following the rapid addition of water to the carbonyl group with the formation of stable hydrates. The involvement of stable carbonyl hydrates in the hydrolysis of dimethyl acetylphosphonate and aroylphosphonates was established by H NMR and UV spectroscopy, respectively. In the latter case, the rates of formation and decomposition of the tetrahedral carbonyl hydrates were also determined. 

In another study chlorotrimethylsilane alone was reported to convert dimethyl acetylphosphonate into the trimethylsilyl enol ether. This is a general type of reaction. 

Kluger et al. [234] have shown that the hydrolysis (neutral aqueous solution) of dimethyl acetylphosphonate (DAP) results in cleavage of the carbonyl-to-phosphonyl... 

According to the literature [1], phosphonate or phosphinate salts could be generally synthesized by the reaction of the corresponding phosphonate or phosphinate esters with inorganic alkalis or salts. For example, as shown in Scheme 3.6, Baillie reported that sodium (9-methyl acetylphosphonate 1-1 could be obtained by demethylation of (9, (9-dimethyl acetylphosphonate 1-la with sodium iodide in butanone [1,5]. The phosphinate 2a could be hydrolyzed to give the corresponding salts 2 in 2 M sodium hydroxide aqueous solution [1]. 

Phosphoenol acetylphosphonate (48) and its dimethyl ester (49) were examined as potential inhibitors of three phosphoenopyruvate (PEP) enzymes ". Both compounds inhibited enolase and PEP carboxylase but they did not bind to pyruvate kinase. Neither compounds was a substrate for any of the enzymes. 

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