1: With potassium nitrate; trifluoroacetic anhydride T=20°C; 12 h; 2: With potassium carbonate T=20°C; 0.5 h;

1: 4-chloro-3-fluoroaniline With hydrogenchloride; sodium nitrite in water T=0°C; 0.5 h; 2: With sodium acetate in water 0.5 h; 3: 2-methyl-3-oxobutanoic acid ethyl ester With potassium acetate more than 3 stages;

1.1: n-heptane / 4 h / 90 °C / Inert atmosphere 2.1: n-butyllithium / tetrahydrofuran; hexane / 2.67 h / -80 - -75 °C / Inert atmosphere 2.2: 17 h / -80 - -30 °C / Inert atmosphere 3.1: hydrogenchloride; water / ethanol / 2 h / 5 - 55 °C / Inert atmosphere 3.2: 1 h / 5 - 15 °C / Inert atmosphere 4.1: 1,4-diaza-bicyclo[2.2.2]octane / N,N-dimethyl-formamide / 20 - 36 °C / Inert atmosphere 4.2: 18 h / 20 - 100 °C / Inert atmosphere 5.1: 1,1'-carbonyldiimidazole / N,N-dimethyl-formamide / 3 h / 20 - 25 °C / Inert atmosphere 5.2: 3 h / 20 - 25 °C / Inert atmosphere View Scheme