1: 2-fluoro-5-chloropyridine With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran; n-heptane T=-78°C; 1 h; 2: carbon dioxide in tetrahydrofuran; n-heptane T=-78 - 20°C; 0.666667 h;

1: With lithium diisopropyl amide T=-78°C; 7 h; 2: With iodine 2 h;

1.1: N-ethyl-N,N-diisopropylamine; n-butyllithium / tetrahydrofuran / 1.5 h / -78 °C 1.2: 0.03 h 2.1: toluene-4-sulfonic acid / toluene / 3 h / Reflux 3.1: hydrazine; N-ethyl-N,N-diisopropylamine / isopropyl alcohol / 65 °C View Scheme

1.1: N-ethyl-N,N-diisopropylamine; n-butyllithium / tetrahydrofuran / 1.5 h / -78 °C 1.2: 0.03 h 2.1: toluene-4-sulfonic acid / toluene / 3 h / Reflux 3.1: hydrazine; N-ethyl-N,N-diisopropylamine / isopropyl alcohol / 65 °C 4.1: N-iodo-succinimide / 1,2-dichloro-ethane / 64 h / 20 - 50 °C View Scheme

1: 2-fluoro-5-chloropyridine With 2,2,6,6-tetramethyl-piperidine; n-butyllithium in tetrahydrofuran; n-heptane T=-78°C; 1 h; 2: carbon dioxide in tetrahydrofuran; n-heptane T=-78 - 20°C; 0.666667 h;