Benzoylacetoacetic ester

The acylation of simple /3-keto esters with acyl chlorides to form di-acylacetic esters proceeds readily however, the subsequent cleavage for removing the smaller acyl group is complicated in that the original keto ester may be regenerated. The optimum conditions for the conversion of benzoylacetoacetic ester to benzoylacetic ester with ammonium chloride and ammonium hydroxide have been studied. The over-all synthesis of this ester has been described (57%). An improved procedure for the ammonolysis of ethyl a-acetyl-/3-oxocaproate using gaseous ammonia has been described. By a similar process, a series of alicyclic /3-keto esters has been prepared in over-all yields of 20-40%. ... 

Shriner and Schmidt161 have described the following similar procedure for preparation of benzoylacetic ester from benzoylacetoacetic ester by gentle warming with an aqueous solution of ammonia and ammonium chloride ... 

The reactivity of the p-keto-ester coupling partner toward less electron-rich phenols is enhanced by substitution of the a-carbon with electron-withdrawing groups e.g., the benzoyl group of benzoylacetoacetate... 

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