1: alpha-chloropyridine With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-70°C; 3 h; Inert atmosphere; 2: acetaldehyde in tetrahydrofuran; hexane T=-70°C; 3 h; 3: With hydrogenchloride; water in tetrahydrofuran; hexane T=-40°C;

1: With n-butyllithium; diisopropylamine in tetrahydrofuran T=-70 - 0°C; 1 h; 2: alpha-chloropyridine in tetrahydrofuran T=-70°C; 3 h; 3: acetaldehyde in tetrahydrofuran T=-70°C; 3 h;

1: chromium(VI) oxide / acetone / 3.25 h / -30 - 20 °C / Inert atmosphere 2: hydrazine hydrate / butan-1-ol / Reflux 3: sodium hydroxide; water; potassium permanganate / 80 - 90 °C 4: sulfuric acid / 6 h / Reflux; Inert atmosphere 5: sodium acetate; bromine; acetic acid / 120 °C / in a sealed tube View Scheme

1.1: chromium(VI) oxide / acetone / 3.25 h / -30 - 20 °C / Inert atmosphere 2.1: hydrazine hydrate / butan-1-ol / Reflux 3.1: sodium hydroxide; water; potassium permanganate / 80 - 90 °C 4.1: sulfuric acid / 6 h / Reflux; Inert atmosphere 5.1: sodium acetate; bromine; acetic acid / 120 °C / in a sealed tube 6.1: sodium hydroxide; water / 3 h / 90 °C 6.2: 0 °C View Scheme

1: 95 percent / chromic anhydride / acetone / 3 h / Ambient temperature 2: 72 percent / 3percentH2O2 / aq. HCl / 20 h / Heating View Scheme

chromium(VI) oxide in acetone 3 h; Ambient temperature;

1: 95 percent / chromic anhydride / acetone / 3 h / Ambient temperature 2: 90 percent / aq. ammonia / 2 h / 100 °C View Scheme

1.1: chromium(VI) oxide / acetone / 3 h / -30 - 20 °C / Inert atmosphere 2.1: hydrazine hydrate / ethanol / 12 h / Reflux 3.1: sodium hydroxide / water / 0.17 h / 20 °C 3.2: 80 °C 3.3: pH 2 View Scheme

1: chromium(VI) oxide / acetone / 3 h / -30 - 20 °C / Inert atmosphere 2: hydrazine hydrate / ethanol / 12 h / Reflux View Scheme

1: 95 percent / chromic anhydride / acetone / 3 h / Ambient temperature 2: 1) MeOH, reflux, 7 h 2) hydrolysis View Scheme