1: (1R)-1-[(3,4-dimethoxyphenyl)-methyl]-1,2,3,4-tetrahydro-6,7-dimethoxy-2-tert-butoxycarbonylethyl-isoquinoline oxalate With sodium hydroxide in water; toluene T=20°C; pH=9 - 10; 0.25 h; 2: benzenesulphonic acid methyl ester in acetonitrile T=30°C; 20 h;

1: (R)-N-(2-tert-butoxycarbonylethyl)-1,2,3,4-tetrahydropapaverine oxalate With sodium hydroxide in water pH=10; 2: benzenesulphonic acid methyl ester in acetonitrile T=30 - 35°C; 24 h;

trifluoroacetic acid T=0 - 5°C; 0.333333 h; Product distribution / selectivity;

Na(1+)*HSO4(1-)*SiO2 = NaHSO4*SiO2 in dichloromethane 34 h; Heating / reflux; Product distribution / selectivity;