Sodioacetoacetic ester

Natr-acetessigester, m. sodioacetoacetic ester, -amid, n. sodamide, sodium amide. 

Acetoacetic ester is converted by sodiunL thexide into the sodioacetoacetic ester, which is then allowed to react with aa alkyl halide to form an alkylaceto-acetic ester (an ethyl alkylacetoacetate), CH3COCHRCOOC2H5 if desired, the alkylation can be repeated to yield a dialkylacetoacetic ester, CH3COCRR COO-C2H5. All alkylations are conducted in absolute alcohol. 

Problem 26.6 To what general class does the reaction between sodioacetoacetic ester and an alkyl halide belong Predict the relative yields using primary, secondary, and tertiary halides. Can aryl halides be used ... 

Explain how compounds with the following general structure are formed as occasional side products of sodioacetoacetic ester alkylations. 

STRATEGY AND ANSWER The partially negative oxygen atom of the sodioacetoacetic ester enolate acts as a nucleophile. 

The acetoacetic ester synthesis generally gives best yields when primary halides are used in the alkylation step. Secondary halides give low yields, and tertiary halides give practically no alkylation product at all. (a) Explain, (b) What products would you expect fiom the reaction of sodioacetoacetic ester and tert-butyl bromide (c) Bromobenzene caimot be nsed as an aryl-ating agent in an acetoacetic ester synthesis in the maimer we have jnst described. Why not ... 

The ABD fragment was obtained by another route in the synthesis of derivatives of 17-carboxyequilenin by Scheme 31 (yields in the scheme given for R = H). The starting material for the production of the 3-deoxy analogs [415] was a-chloromethylnaphthalene (323), which by reaction with sodioacetoacetic ester and alkaline decomposition gave the ketone (324 ... 

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