formic acid; iron; zinc T=60 - 65°C; 2 h;

lithium hydroxide T=60°C; 2.5 h;

1.1: NaBH4 / methanol / 20 °C 2.1: SOCl2; benzotriazole / CH2Cl2 3.1: NaH / dimethylformamide; various solvent(s) / 0.5 h / 20 °C 3.2: 81 percent / dimethylformamide; various solvent(s) / 7 h / 20 - 60 °C 4.1: NaOH / methanol / 20 h / 20 °C 5.1: toluene / 2 h / Heating 6.1: 74 percent / aq. LiOH / 2.5 h / 60 °C View Scheme

1.1: NaH / dimethylformamide; various solvent(s) / 0.5 h / 20 °C 1.2: 81 percent / dimethylformamide; various solvent(s) / 7 h / 20 - 60 °C 2.1: NaOH / methanol / 20 h / 20 °C 3.1: toluene / 2 h / Heating 4.1: 74 percent / aq. LiOH / 2.5 h / 60 °C View Scheme

1.1: SOCl2; benzotriazole / CH2Cl2 2.1: NaH / dimethylformamide; various solvent(s) / 0.5 h / 20 °C 2.2: 81 percent / dimethylformamide; various solvent(s) / 7 h / 20 - 60 °C 3.1: NaOH / methanol / 20 h / 20 °C 4.1: toluene / 2 h / Heating 5.1: 74 percent / aq. LiOH / 2.5 h / 60 °C View Scheme

1: NaOH / methanol / 20 h / 20 °C 2: toluene / 2 h / Heating 3: 74 percent / aq. LiOH / 2.5 h / 60 °C View Scheme

1: toluene / 2 h / Heating 2: 74 percent / aq. LiOH / 2.5 h / 60 °C View Scheme