Step 2. Synthesis of (3-methyl-4-nitrophenyl)acetic acid
To a mixed solution of dimethyl (3-methyl-4-nitrophenyl) malonate (0.540 g, 2.02 mmol) in water (10 mL) and methanol (10 mL) was added potassium hydroxide (0.340 g, 6.06 mmol) at room temperature. The reaction mixture was refluxed for 4 hours. After completion of the reaction, it was cooled to room temperature and acidified with 2N aqueous hydrochloric acid solution (40 mL). The acidified solution was extracted with ethyl acetate (20 mL x 3). The organic layers were combined, dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to give (3-methyl-4-nitrophenyl)acetic acid (0.480 g, quantitative yield) as an orange solid. The product was used directly in the next reaction without further purification.
1H NMR (CDCl3, 400 MHz) δ 7.97 (d, 1H), 7.28-7.26 (m, 2H), 3.71 (s, 2H), 2.61 (s, 3H).
