Sodium Hydroxide → 3,5-Dimethyldodecanoic acid

In a nitrogen atmosphere, ethyl 2-(1,3-dimethyldecyl)malonate (4Et) (35.2 g, 0.107 mol) and a 13% by weight aqueous sodium hydroxide solution (104 g) were placed in a reaction vessel and stirred under refluxing with heating for one hour. Then, the resulting ethanol therein was distilled off in one hour. A 56% by weight aqueous sulfuric acid solution (93 g) was added thereto and the resulting mixture was under refluxing with heating for 30 hours. The reaction mixture was diluted with tetrahydrofuran. The organic phase was washed three times with an aqueous saturated sodium chloride solution and concentrated under reduced pressure. The concentrate thus obtained was distilled under reduced pressure (bp: from 130 to 140° C./2 mmHg) to obtain 3,5-dimethyldodecanoic acid (5) (21.6 g, 0.0944 mol). A total yield of three steps from the 2-methylnonyl chloride (1Cl) was 59%.