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.
Inhibition of photosystem II electron transport by acyl derivatives of 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid)