866783-12-2

866783-13-3

The general procedure for the synthesis of (1S)-4,5-dimethoxy-1-methylaminomethyl-benzocyclobutane hydrochloride from (S)-1-(3,4-dimethoxybicyclo[4.2.0]octa-1,3,5-trien-7-yl)-N-methylmethylamine is as follows: (1S)-4,5-dimethoxy-1-methylaminomethyl-benzocyclobutane hydrochloride, which was obtained from the previous step, was was dissolved in a solvent mixture of ethyl acetate (20 mL) and ethanol (5 mL) and stirred at 20 °C. Subsequently, hydrogen chloride gas was passed into the reaction solution and stirring was continued at 15 °C - 20 °C for 1 hour until the reaction solution became turbid. After completion of the reaction, the reaction mixture was washed with a mixed solvent of ethyl acetate/ethanol (4:1, v/v) and dried to afford (1S)-4,5-dimethoxy-1-[(methylamino)methyl]benzocyclobutane hydrochloride (2.38 g, 95% yield).