1.1: conc. HCl / methanol / 0.5 h / 20 °C 1.2: 99 percent / hydrazine hydrate / ethanol / 1 h / Heating 2.1: 99 percent / TsOH / toluene / 0.5 h / Heating 3.1: 60 percent / toluene; diethyl ether / 0.42 h / -20 °C 4.1: Mo(CO)6 / acetonitrile; H2O / 1 h / 85 °C View Scheme

1.1: conc. HCl / methanol / 0.5 h / 20 °C 1.2: 99 percent / hydrazine hydrate / ethanol / 1 h / Heating 2.1: 99 percent / TsOH / toluene / 0.5 h / Heating 3.1: 60 percent / toluene; diethyl ether / 0.42 h / -20 °C 4.1: Mo(CO)6 / acetonitrile; H2O / 1 h / 85 °C 5.1: 81 percent / triphenylphosphine; diethyl azodicarboxylate / tetrahydrofuran / 48 h / 20 °C 6.1: 99 percent / hydrazine hydrate / ethanol / 1 h / Heating 7.1: 99 percent / TsOH / toluene / 0.5 h / Heating 8.1: toluene; diethyl ether / 0.42 h / 0 °C 9.1: zinc / acetic acid; tetrahydrofuran; H2O / 4 h / 60 °C View Scheme