2,6-Dimethylaniline → 2,6-Dimethylphenylhydrazine hydrochloride

To a cold (0° C.) solution of 2,6-dimethylaniline (5.0 g, 41.3 mmol) in 50% aqueous HCl (45 mL), was added slowly under stirring a cold (0° C.) solution of NaNO2 (2.85 g, 41.3 mmol) in water (22.5 mL). The temperature was closely monitored during the addition and was not allowed to exceed 5° C. Upon completion of the addition, the bright orange solution containing the diazonium salt intermediate was stirred at the same temperature for 20 min. A mixture of SnCl2 (11.0 g, 57.8 mmol) in conc HCl (30 mL) was added to the reaction mixture at 0° C. over a period of ˜5 min. The reaction mixture was then warmed to rt and stirred for 6 h. The precipitate was collected by filtration and washed with a small volume of cold water. Drying in vacuo afforded the title compound as a white amorphous solid (7.00 g, 98%). The product was used in the next step without further purification. ES-MS m/z 137.0 (MH+); HPLC RT (min) 1.09.