The chemistry of aryllead(IV) tricarboxylates. Reaction with derivatives of malonic acid: New routes to α-aryl carboxylic acids and arylated barbituric acid derivatives

Abstract

Derivatives of 2,2-dimethyl-1,3-dioxan-4,6-dione (Meldrum's acid) and the sodium salts of substituted malonic esters undergo electrophilic C-arylation in high yield with aryllead triacetates, thus providingnew routes to α-arylalkanoic acids. Syntheses of the antiflammatory compound 2-(p-isobutylphenyl)-propanoic acid (Ibuprofen) have been carried out to demonstrate the method. The arylation reactionhas been extended to 5-ethylbarbituric acid and to barbituric acid itself, which affords the 5,5-diarylated derivatives in good yield. A study of the effect of some tertiary bases on there action of p-methoxyphenyllead triacetate with the 5-isopropyl derivative of Meldrum's acid has shown that replacement of pyridine by 2,2'-bipyridyl results in an increase in yield and reaction rate, while a further marked improvement occurs in the presence of 1,10-phenanthroline.