1: toluene-p-sulphonic acid / CH2Cl2 / 1.5 h / Ambient temperature 2: 63 percent / H2 / 10percent palladized charcoal / tetrahydrofuran / Ambient temperature 3: 58 percent / 1.) trifluoroacetic acid, 2.) sodium acetate / methanol; CH2Cl2 / 1.) 2-3 deg C 90 min, 2.) 18 deg C 5 min, 3.) 50 min 4: 1.) 2M aq. potassium hydroxide; 2.) sodium amalgam / 1.) tetrahydrofuran 20 deg C; 2.) 3-4 min 5: 0.5 h / coproporphyrinogen-III oxidase (from Euglena gracilis) View Scheme

1: 77 percent / p-toluene sulfonic acid hydrate / acetic acid / 4 h / 45 °C 2: 98 percent / triethylamine, H2 / 10percent palladised charcoal / tetrahydrofuran / 760 Torr / Ambient temperature 3: 1) p-toluene sulfonic acid hydrate; 2) calcium carbonate, phosphoryl chloride / 1) dichloromethane, methanol, 40 min, room temperature; 2) 1.5h, room temperature 4: 85 percent / 1) toluene p-sulfonic acid hydrate; 2) HBr / CH2Cl2; methanol / 16 h 5: 42 percent / trifluoroacetic acid / 0.25 h / Ambient temperature 6: 54 percent / 3percent aqeous sodium hydroxide / pyridine / 2.5 h / Heating View Scheme

1: toluene-p-sulphonic acid / CH2Cl2 / 1.5 h / Ambient temperature 2: 63 percent / H2 / 10percent palladized charcoal / tetrahydrofuran / Ambient temperature 3: 58 percent / 1.) trifluoroacetic acid, 2.) sodium acetate / methanol; CH2Cl2 / 1.) 2-3 deg C 90 min, 2.) 18 deg C 5 min, 3.) 50 min 4: 1.) 2M aq. potassium hydroxide; 2.) sodium amalgam / 1.) tetrahydrofuran 20 deg C; 2.) 3-4 min View Scheme