chlorosulfonic acid 1 h; Ambient temperature;

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h View Scheme

sulfuric acid; zinc in water 16 h; Heating;

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h View Scheme

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h 3: 97 percent / 0.94 N borane / tetrahydrofuran / 1 h / Heating View Scheme

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h 3: 74 percent / 1.0 M borane / tetrahydrofuran / 1 h / Heating View Scheme

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h 3: 74 percent / 1.0 M borane / tetrahydrofuran / 1 h / Heating 4: 63 percent / sodium hydride / bis-(2-methoxy-ethyl) ether / 1 h / Heating 5: 67 percent / pyridine hydrochloride / 6 h / 180 °C View Scheme

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h 3: 74 percent / 1.0 M borane / tetrahydrofuran / 1 h / Heating 4: 63 percent / sodium hydride / bis-(2-methoxy-ethyl) ether / 1 h / Heating 5: 67 percent / pyridine hydrochloride / 6 h / 180 °C 6: 83 percent / potassium carbonate / butan-2-one / 3 h / Heating 7: 69 percent / 20percent sodium hydroxide; conc.HCl / ethanol / 2 h / Heating View Scheme

1: 88 percent / conc. sulfuric acid, zinc dust / H2O / 16 h / Heating 2: 1) sodium hydride; 2) 3N HCl / 1) DMF, 10 min; 2) room temp., 3 h 3: 97 percent / 0.94 N borane / tetrahydrofuran / 1 h / Heating 4: 15 percent / sodium hydride / dimethylsulfoxide / 1) room temp., 30 min; 2) 90 deg C, 1 h View Scheme