Ethyl benzalmalonate

ETHYL BENZALMALONATE (Malonic acid, benzal-, diethyl ester) 

Submitted by C. F. H. Allen and F. W. Spangler. Checked by R. L. Shriner and Fred W. Neumann. 

Syntheses, 24, 72 (1944). The column can be purchased from the Precision Optical Company, Rochester, New York. 

Commercial benzaldehyde which contains 2-8% of benzoic acid is eminently satisfactory. The acid content is determined (conveniently by titration of a sample in neutral ethanol with standard alkali), and a quantity of aldehyde containing 70 g. (0.66 mole) of benzaldehyde is used. The checkers used 76 g. of commercial benzaldehyde which contained 8% of benzoic acid. If pure benzaldehyde is employed, then 2 g. of benzoic acid should be added. 

It has been shown3 that piperidine salts and not the free base act as the catalyst in the Rnoevenagel reaction. The checkers obtained only a 71% yield with benzaldehyde containing less than 0.2% of benzoic acid. 

A mixture of 100 g. (0.63 mole) of dry malonic ester and 70 g. (0.66 mole) of benzaldehyde is placed in a 200-ml. thick-walled vessel, and 2 g. of piperidine is added gradually. The reaction vessel is stoppered securely and allowed to stand for 2 days. The reaction mixture is then heated on a water bath for 12 hours. Ether is added, and the resulting solution is washed with dilute aqueous acid and then with water. The ethereal solution is dried over anhydrous sodium sulfate and distilled. There is obtained a 70% yield of ethyl benzalmalonate boiling at 185-186°/11 mm. and melting at 27-27.5°. 

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Ethylamine, 2-chloro-N,N-dimethyl-, HYDROCHLORIDE, 31, 37 N-methyl-1,2-diphenyl-, 34, 64 N-Ethylaniline, 36, 22 Ethyl benzalmalonate, 37, 5 Ethyl benzoylacetate, 32, 85 37, 3 Ethyl benzoylacetate, 37, 32 Ethyl N-benzylcarbamate, 35, 91 Ethyl 3-benzyl-2-cyano-3-methylpenta-noate, 35, 7... 

Another boiling point is 179-181°/10 mm. The boiling points reported for ethyl benzalmalonate vary widely. The temperature observed depends on the degree of superheating and the rapidity of distillation. 

Ethyl benzalmalonate has been prepared by the esterification of benzalmalonic acid in the presence of concentrated sulfuric acid 4 by the action of benzal chloride on sodiomalonic ester 6 by the condensation of benzaldehyde and malonic ester in the pres-... 

Ethyl acetoacetate, 29, 214, 399, 540, 629, 794, 887,1075,1128, 1268-1269,1272 p-Ethylacetophenone, 946,1084-1085 Ethyl acetopynivate, 251 Ethyl o-acetoxyacetoacetate, 540 Ethyl o-acetO Qrhexanoic acid, 541 Ethyl acetylacetoacetate, 1097 Ethyl a-acetyl-f3-(2,3-dimethoxyphenyl> propionate, 896 Ethyl acetyl eburicoate, 615 Ethyl acrylate, 928 N-Ethylallenimine, 1637 Ethylamine, 103,372,574,575,578,579,770 Ethyl p-aminobenzoate, 890 Ethyl 3-aminocitrazinate, 520 Ethyl azidoformate, 363-364 Ethyl benzalmalonate, 888 Ethylbenzene, 226,567,576, 719, 779,1061, 1287... 

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