To a reflux apparatus add 50 mL of water 20.4 g of 2,5-dimethoxytetrahydrofuran and 2 mL of conc. HCI, heat under 70-75°C for 30 minutes. Cool the solution down to room temperature. To a 500 mL RBF with nitrogen inlet add 150 mL of water, 50 g of sodium acetate 15 mL of 40 % methylamine hydrochloride solution and 24.8 g acetonedicarboxylic acid. With stirring add the first solution to the RBF over the course of 10 minutes. Stir for an hour at 40°C with stirring, cool down and alkalinize the solution to pH 10, add 40 g of sodium chloride. Extract the tropinone with 3x 85 mL of DCM. Evaporate the DCM off and recrystallize in ethanol.