[Synthesis]
The general procedure for the synthesis of 2-amino-3-methylbenzonitrile from 2-bromo-6-methylaniline and cuprous cyanide was as follows: cuprous cyanide (CuCN, 197 mg, 2.2 mmol) was added to an anhydrous N-methylpyrrolidone (NMP, 3 mL) solution of 2-bromo-6-methylaniline (126 μL, 1 mmol). The reaction mixture was placed in a microwave reactor and irradiated at 220 °C for 40 min. Upon completion of the reaction, the mixture was cooled to room temperature and poured into a mixture consisting of ammonia (50% w/v, 10 mL) and ice. Subsequently, the mixture was stirred for 30 min and the target product was extracted with dichloromethane (3 x 20 mL). The organic layers were combined, washed sequentially with water and saturated saline, dried with anhydrous magnesium sulfate (MgSO4), and then concentrated. The crude product was purified by silica gel column chromatography (eluent: 50% ethyl acetate/hexane) to give a brown oil, which was crystallized after standing (128 mg, 96% yield). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6) and mass spectrometry (MS): 1H NMR δ 2.08 (s, 3H), 5.68 (bs, 2H), 6.51-6.55 (t, 1H), 7.17-7.19 (d, 1H), 7.22-7.24 (dd, 1H); MS m/z 133 ([M+H ]+). |