In a study of alkyl malonic nitriles, carried out some years ago,' the writer found that the Conrad-Limpach reaction, which was used for the preparation of ethylcyanoacetic ester, gave a mixture containing about 30% of diethylcyanoacetic ester. In this experiment ethyl iodide was used as the alkylating-material. Recent experiments by Hadley,2 carried out under the writer's direction, show that when ethyl bromide is used, practically the same amount (28%) of diethylcyanoacetic ester is formed. The present paper describes the results obtained in the alkylation of cyanoacetic ester by means of methyl, isopropyl, and isoamyl iodides. The investigation is being extended to include the alkylation of several esters of cyanoacetic acid and the use, as solvents, of other alcohols than ethyl alcohol, especially methyl and isoamyl alcohols. Experimental. Derivatives of Methylcyanoacetic Ester. (a) Preparation of the Crude Ester.-The method was that of Henry:3 20 grams of cyanoacetic ester, dissolved in 80 grams of absolute alcohol, were treated with 4.07 grams of sodium, also dissolved in 80 grams of absolute alcohol, and to the resulting sodium salt there was added a slight excess (26.2 grams) of methyl iodide. The mixture became hot, and was cooled with running water. I t was neutral to litmus in five minutes. The alcohol was then distilled off, water was added, and the product was extracted with ether. The ether was dried with calcium chloride. When the ether solution was fractionated, there were obtained 17.1 grams of a fragrant liquid boiling a t 8 7 '-90 O under I 2 mm. This is 72 % of the theoretical amount, (b) Dimethylcyanoacetic Ester.-The crude ester obtained in the methylation of cyanoacetic ester was shaken four times, in ether solution, with 10% sodium hydroxide solution, and the ether solution was dried with calcium chloride. When it was fractionated, it gave 2.1 grams, i. e., 12.3%) of dimethylcyanoacetic ester. This is a colorless, ethereal liquid boiling a t 7 7 O under 9 mm., and a t 185 O under ordinary pressure. An analysis gave the following result :
