1: 53 percent / toluene / 2 h 2: 63 percent / Zn, glacial acetic acid / dioxane / 4 h / Ambient temperature View Scheme

formic acid in water T=20 - 100°C; Pictet-Spengler Synthesis; 2 h;

1: 1,2,3,4-Tetrahydro-6,7-dimethoxyisoquinoline hydrochloride With sodium hydroxide in dichloromethane; water Inert atmosphere; 2: formaldehyd With formic acid in water T=100°C; Inert atmosphere;

sodium tetrahydroborate in ethanol; water 4 h; Ambient temperature;

sodium tetrahydroborate in methanol T=25°C; 7 h;

1.1: 98 percent / NaBH4 / tetrahydrofuran; methanol / 2 h 2.1: SOCl2 / benzene / 20 °C 3.1: dimethylsulfoxide; benzene / 2 h 4.1: 92 percent / 4N NaOH / ethanol / 20 h / Heating 5.1: SOCl2 / benzene / 2 h / 50 - 60 °C 6.1: 91 percent / benzene; pyridine / 20 °C 7.1: 85 percent / POCl3 / toluene / 3 h / Heating 8.1: 92 percent / methylene blue; O2 / CH2Cl2; methanol / 0.5 h / 15 °C / Irradiation 9.1: 82 percent / acetonitrile / 1.25 h / Heating 10.1: 92 percent / H2 / PtO2 / methanol / 3 h / 17 °C 11.1: 90 percent / NaBH4 / methanol / 2 h 12.1: CuCl2 / toluene / 0.03 h / 140 °C 12.2: NaBH4 / methanol / 2 h / 20 °C View Scheme

1.1: 92 percent / 4N NaOH / ethanol / 20 h / Heating 2.1: SOCl2 / benzene / 2 h / 50 - 60 °C 3.1: 91 percent / benzene; pyridine / 20 °C 4.1: 85 percent / POCl3 / toluene / 3 h / Heating 5.1: 92 percent / methylene blue; O2 / CH2Cl2; methanol / 0.5 h / 15 °C / Irradiation 6.1: 82 percent / acetonitrile / 1.25 h / Heating 7.1: 92 percent / H2 / PtO2 / methanol / 3 h / 17 °C 8.1: 90 percent / NaBH4 / methanol / 2 h 9.1: CuCl2 / toluene / 0.03 h / 140 °C 9.2: NaBH4 / methanol / 2 h / 20 °C View Scheme

1.1: SOCl2 / benzene / 20 °C 2.1: dimethylsulfoxide; benzene / 2 h 3.1: 92 percent / 4N NaOH / ethanol / 20 h / Heating 4.1: SOCl2 / benzene / 2 h / 50 - 60 °C 5.1: 91 percent / benzene; pyridine / 20 °C 6.1: 85 percent / POCl3 / toluene / 3 h / Heating 7.1: 92 percent / methylene blue; O2 / CH2Cl2; methanol / 0.5 h / 15 °C / Irradiation 8.1: 82 percent / acetonitrile / 1.25 h / Heating 9.1: 92 percent / H2 / PtO2 / methanol / 3 h / 17 °C 10.1: 90 percent / NaBH4 / methanol / 2 h 11.1: CuCl2 / toluene / 0.03 h / 140 °C 11.2: NaBH4 / methanol / 2 h / 20 °C View Scheme

1.1: dimethylsulfoxide; benzene / 2 h 2.1: 92 percent / 4N NaOH / ethanol / 20 h / Heating 3.1: SOCl2 / benzene / 2 h / 50 - 60 °C 4.1: 91 percent / benzene; pyridine / 20 °C 5.1: 85 percent / POCl3 / toluene / 3 h / Heating 6.1: 92 percent / methylene blue; O2 / CH2Cl2; methanol / 0.5 h / 15 °C / Irradiation 7.1: 82 percent / acetonitrile / 1.25 h / Heating 8.1: 92 percent / H2 / PtO2 / methanol / 3 h / 17 °C 9.1: 90 percent / NaBH4 / methanol / 2 h 10.1: CuCl2 / toluene / 0.03 h / 140 °C 10.2: NaBH4 / methanol / 2 h / 20 °C View Scheme

1.1: 91 percent / benzene; pyridine / 20 °C 2.1: 85 percent / POCl3 / toluene / 3 h / Heating 3.1: 92 percent / methylene blue; O2 / CH2Cl2; methanol / 0.5 h / 15 °C / Irradiation 4.1: 82 percent / acetonitrile / 1.25 h / Heating 5.1: 92 percent / H2 / PtO2 / methanol / 3 h / 17 °C 6.1: 90 percent / NaBH4 / methanol / 2 h 7.1: CuCl2 / toluene / 0.03 h / 140 °C 7.2: NaBH4 / methanol / 2 h / 20 °C View Scheme