o-Toluidine hydrochloride

88-72-2

636-21-5

The general procedure for the synthesis of o-biphenylamine hydrochloride from o-nitrotoluene was as follows: the catalyst precursor in the form of 0.04 M CuSO4 and 0.004 M CoCl2 solution (3.0 ml, 3.0 mol/mol CuSO4, 0.3 mol/ml CoCl2) was added to magnetically stirred 25 ml methanol solution of o-nitrotoluene (4 mmol). The reaction was initiated by the addition of an initial portion of 210 mg (5.6 mmol) of NaBH4, and a change in the color of the reaction solution to black (in situ generated catalyst) accompanied by the escape of violent gases was observed. Subsequently, NaBH4 (7 × 35 mg, 7 × 0.9 mmol) was added in portions at 3 min intervals. The reaction was carried out at room temperature and atmospheric pressure, and due to the exothermic nature of the reaction, the temperature of the reaction mixture was usually raised to 30-40 °C, and additional cooling was usually not required for small-scale reactions. For large scale reactions (10 mmol), a reflux condenser needs to be connected. After 25 minutes of reaction, the reaction was quenched by adding 30 ml of water and extracted with 3 x 40 ml of CH2Cl2. The organic layers were combined and dried with MgSO4. After removal of the desiccant, an ether solution (10 ml) of 6 M HCl was added to form a more stable hydrochloride, followed by removal of excess HCl, CH2Cl2, and Et2O under reduced pressure (10 mmHg).The amine products were analyzed by GC-MS, 1H-NMR, and 13C-NMR. The NMR data of the compounds are listed in Table 2.