zinc in acetic acid 1.) 15 deg C, 1.5 h; 2.) rooom temperature, 6 h;

1: 15 percent / H2 / 10percent Pd/C / ethanol / 2 h / Ambient temperature 2: 7 percent / aq. NaNO2 / aq. H2SO4 / 1.) 0 deg C, 0.5 h; 2.) room temperature, overnight View Scheme

sodium nitrite in sulfuric acid 1.) 0 deg C, 0.5 h; 2.) room temperature, overnight;