116599-06-5

3663-35-2

116599-06-5

(b) Preparation of 4-ethyl-1,2-phenylenediamine: 5.7 g (34.3 mmol) of 4-ethyl-2-nitroaniline was dissolved in 150 mL of ethanol, and the hydrogenation reaction was carried out over 1.8 g of 5% Pd/C catalyst at atmospheric pressure using an Ishii catalytic hydrogenation unit and a magnetic stirrer of the CHA-M type. Upon completion of the reaction, the catalyst was removed by filtration and the solvent was evaporated under reduced pressure to give 4 g of an oily product. Subsequently, 6 g (58.8 mmol) of concentrated hydrochloric acid was added to this oily product to give 5.4 g (75.33% yield) of 4-ethyl-1,2-benzenediamine dihydrochloride.