Ethyl sec -butylmalonate

A solution of 200 g. (3.57 moles) of potassium hydroxide (Note 1) in 200 cc. of water is placed in a 2-1. round-bottom flask fitted with a reflux condenser, a mechanical stirrer and a separatory funnel. The stirrer is started and to the hot solution 200 g. (0.92 mole) of ethyl sec.-butylmalonate (Note 2) is added slowly. The solution refluxes gently due to the heat of saponification. After all of the sec.-butylmalonic ester has been added, the solution is refluxed gently for two hours. The solution is diluted with 200 cc. of water and 200 cc. of liquid is then distilled from the solution. This is done in order to remove all of the alcohol formed during the saponification (Note 3). 

The ethyl sec,-butylmalonate was prepared from sec-butyl bromide and malonic ester according to the general method described in Org. Syn. 4, n. The yield of ester boiling at i24-i32°/28 mm. was 80-81 per cent of the theoretical amount. The yields of 3-methyl pentanoic acid given in this procedure were obtained with this grade of ester. 

---