1: 9,9-Dimethoxyxanthene With potassium tert-butylate; tert.-butyl lithium in hexane; (+/-)-Tetrahydropapaveroline Inert atmosphere; 2: methyl iodide in hexane; (+/-)-Tetrahydropapaveroline Inert atmosphere; 3: With water in hexane; (+/-)-Tetrahydropapaveroline Acidic conditionsInert atmosphere;

1: 9,9-Dimethoxyxanthene With tert.-butyl lithium in hexane; (+/-)-Tetrahydropapaveroline T=-40 - -30°C; 0.533333 h; Inert atmosphere; 2: methyl iodide in hexane; (+/-)-Tetrahydropapaveroline T=-50 - 20°C; Inert atmosphere; 3: With hydrogenchloride; water in methanol; hexane; (+/-)-Tetrahydropapaveroline pH=3; Inert atmosphere; regioselective reaction;

1: 9,9-Dimethoxyxanthene With n-butyllithium in (+/-)-Tetrahydropapaveroline T=-13 - -10°C; 2: methylation agent in (+/-)-Tetrahydropapaveroline 3: Acidic aq. solution;

1: 9,9-Dimethoxyxanthene With tert.-butyl lithium in hexane; (+/-)-Tetrahydropapaveroline T=-40 - -30°C; 0.533333 h; Inert atmosphere; 2: methyl iodide in hexane; (+/-)-Tetrahydropapaveroline T=-50 - 20°C; Inert atmosphere; 3: With hydrogenchloride; water in methanol; hexane; (+/-)-Tetrahydropapaveroline pH=3; Inert atmosphere; regioselective reaction;

1: 9,9-Dimethoxyxanthene With n-butyllithium in (+/-)-Tetrahydropapaveroline T=-13 - -10°C; 2: methylation agent in (+/-)-Tetrahydropapaveroline 3: Acidic aq. solution;

1: 9,9-Dimethoxyxanthene With potassium tert-butylate; tert.-butyl lithium in hexane; (+/-)-Tetrahydropapaveroline Inert atmosphere; 2: methyl iodide in hexane; (+/-)-Tetrahydropapaveroline Inert atmosphere; 3: With water in hexane; (+/-)-Tetrahydropapaveroline Acidic conditionsInert atmosphere;