1: With sodium hydroxide; water in tetrahydrofuran; methanol 0.5 h; 2: With hydrogenchloride in tetrahydrofuran; methanol; water pH=2;

lithium hydroxide; water in tetrahydrofuran T=25°C; 1 h;

1: 2,4-dichloro-5-iodopyridine With tert.-butyl lithium in diethyl ether; pentane T=-75°C; 0.25 h; 2: carbon dioxide T=-78°C;

1: POCl3 / 115 - 120 °C 2: aqueous NaOH / anschliessend mit POCl3 und PCl5 auf 140grad erwaermen View Scheme

1: acetic anhydride / 145 °C 2: trichlorophosphate / Reflux 3: lithium hydroxide hydrate / tetrahydrofuran; water / 20 °C View Scheme

1.1: 2,2,6,6-tetramethylpiperidine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 76 percent / iodine / tetrahydrofuran 2.1: 79 percent / butyllithium; diisopropylamine / tetrahydrofuran; hexane / 4 h / -75 °C 3.1: isopropylmagnesium chloride / tetrahydrofuran / 1 h / 0 °C 3.2: 67 percent / N-chlorosuccinimide / tetrahydrofuran / 1 h / 25 °C 4.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 4.2: 81 percent / iodine / tetrahydrofuran 5.1: lithium diisopropylamide / tetrahydrofuran; hexane / 2 h / -75 °C 5.2: 26 percent / silica gel; H2O / CH2Cl2; hexane 6.1: tert-butyllithium / pentane; diethyl ether / 0.25 h / -75 °C 6.2: 79 percent / -78 °C View Scheme

1.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 81 percent / iodine / tetrahydrofuran 2.1: lithium diisopropylamide / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 26 percent / silica gel; H2O / CH2Cl2; hexane 3.1: tert-butyllithium / pentane; diethyl ether / 0.25 h / -75 °C 3.2: 79 percent / -78 °C View Scheme

1.1: isopropylmagnesium chloride / tetrahydrofuran / 1 h / 0 °C 1.2: 67 percent / N-chlorosuccinimide / tetrahydrofuran / 1 h / 25 °C 2.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 2.2: 81 percent / iodine / tetrahydrofuran 3.1: lithium diisopropylamide / tetrahydrofuran; hexane / 2 h / -75 °C 3.2: 26 percent / silica gel; H2O / CH2Cl2; hexane 4.1: tert-butyllithium / pentane; diethyl ether / 0.25 h / -75 °C 4.2: 79 percent / -78 °C View Scheme

1.1: 79 percent / butyllithium; diisopropylamine / tetrahydrofuran; hexane / 4 h / -75 °C 2.1: isopropylmagnesium chloride / tetrahydrofuran / 1 h / 0 °C 2.2: 67 percent / N-chlorosuccinimide / tetrahydrofuran / 1 h / 25 °C 3.1: diisopropylamine; butyllithium / tetrahydrofuran; hexane / 2 h / -75 °C 3.2: 81 percent / iodine / tetrahydrofuran 4.1: lithium diisopropylamide / tetrahydrofuran; hexane / 2 h / -75 °C 4.2: 26 percent / silica gel; H2O / CH2Cl2; hexane 5.1: tert-butyllithium / pentane; diethyl ether / 0.25 h / -75 °C 5.2: 79 percent / -78 °C View Scheme

1.1: lithium diisopropylamide / tetrahydrofuran; hexane / 2 h / -75 °C 1.2: 26 percent / silica gel; H2O / CH2Cl2; hexane 2.1: tert-butyllithium / pentane; diethyl ether / 0.25 h / -75 °C 2.2: 79 percent / -78 °C View Scheme