2-Methylglutaric acid

Preparation

Step 1: 80g diethyl malonate + 50mL DMF + 14g KF/Al2O3, oil bath 80℃, 50g methyl methacrylate dissolved in 50mL DMF was added dropwise, reaction for 5 hours. After the reaction, GC-MS analysis showed that most of the diethyl malonate was converted, and the chromatographic integral area percentage of the main intermediate was 56%. The solvents DMF and methanol were removed by vacuum distillation, and approximately 70g of product 1 was obtained by vacuum distillation at 160℃. Step 2: 0.1mol of product 1 was hydrolyzed with 0.4mol NaOH at 20℃ for 3 hours, then acidified with 0.4mol sulfuric acid, refluxed at 100℃ for decarboxylation for 4 hours, cooled, separated, and the aqueous phase was extracted with ethyl acetate 5 times. The organic phases were combined, the solvent was removed by vacuum, and GC-MS analysis showed that it was 2-methylglutaric acid (product 2). The chromatographic integral area percentage was 68%, and the yield was 60%.

Chemical Properties

white to almost white fine crystalline powder

Uses

2-Methylglutaric acid was used in the preparation of acetic acid.

Definition

ChEBI: 2-methylglutaric acid is an alpha,omega-dicarboxylic acid that is glutaric acid substituted at position 2 by a methyl group. It has a role as a mammalian metabolite. It is an alpha,omega-dicarboxylic acid and a dicarboxylic fatty acid. It is functionally related to a glutaric acid. It is a conjugate acid of a 2-methylglutarate(2-).

Purification Methods

Crystallise the acid from distilled water, then dry it under vacuum over conc H2SO4. [Beilstein 2 IV 1989.]