Alkylation of CH-Acids with 3-Halomethyl Derivatives of Ethyl (Diethoxyphosphorylmethyl)furoates

Abstract

Alkylation at the carbon atom of the active methylene group of 3-halomethyl derivatives of phosphonocarboxylic acid esters of the furan series with acetylacetone, acetoacetic, malonic and cyanoacetic esters in an absolute ethanol–dioxane medium (1 : 10) in the presence of sodium ethylate leads to the formation of the corresponding monoalkyl derivatives. The obtained phosphonomethylated derivatives of 3-(furylmethyl)acetylacetone and ethyl 2-(furylmethyl)acetoacetate react with hydrazine hydrate to form phosphorus-containing derivatives of (furyl)(pyrazolyl)methanes and (furyl)(pyrazolonyl)methanes, respectively. The latter in chloroform exist exclusively in enol form.