M-Toluic acid
"m"-Toluic acid, (IUPAC: 3-methylbenzoic acid), is an aromatic carboxylic acid, with formula (CH)CH(COOH). It is an isomer of "p"-toluic acid and "o"-toluic acid. Preparation. m-toluic acid is often prepared in the laboratory by refluxing m-xylene with either nitric acid or potassium permanganate, oxidizing one of the methyl groups to COOH. Uses. It serves, among other purposes, as a precursor to DEET ("N","N"-diethyl-"m"-toluamide), the well-known insect repellent: