1: With hydrogen bromide in water 30 h; Heating / reflux; 2: With sodium hydroxide in water

potassium dodecatangestocobaltate trihydrate Skraup reaction; 0.2 h; microwave irradiation;

hydrazine hydrate; palladium on activated charcoal in ethanol Heating;

hydrogenchloride; nitrobenzene

1: 74 percent / NaCNBH3, conc. HCl / ethanol / 1) RT, 1 h, 2) 60 deg C, 2 h, 3) RT, overnight 2: 93 percent / conc. HCl, glacial HOAc / Heating 3: 17 percent / 20percent Pd-C / various solvent(s) / 150 °C View Scheme