1: 85 percent / K2CO3 / dimethylformamide / Ambient temperature 2: 78 percent / NaNO2, acetic acid / ethanol / 0.5 h 3: 1.2 g / Zn, formic acid / tetrahydrofuran; H2O / 1 h / 0 - 5 °C 4: 1M KOH / methanol / Ambient temperature View Scheme