thionyl chloride 15 h; Heating / reflux; Product distribution / selectivity;

1: 3-hydroxypyridine-4-carboxylic acid With 1,1'-carbonyldiimidazole in tetrahydrofuran T=70°C; 1 h; 2: sodium ethanolate in tetrahydrofuran; ethanol Product distribution / selectivity;

1: sulfuric acid / 72 h / |Reflux 2: triphenylphosphine; di-isopropyl azodicarboxylate / tetrahydrofuran / 16 h / -10 - 20 °C 3: sodium hydride / tetrahydrofuran; mineral oil / 16 h / 0 - 20 °C / |Inert atmosphere 4: pyridine / dichloromethane / 16 h / 0 - 20 °C 5: palladium 10 on activated carbon; triethylamine; hydrogen / ethanol / 16 h / 760.05 Torr 6: potassium hydroxide; water / tetrahydrofuran; methanol / 16 h / 20 °C View Scheme

1: 83 percent / 98percent H2SO4 / benzene / 48 h / Heating 2: 81 percent / K2CO3 anhydr. / acetone / 2 h / Heating 3: 60 percent / Na / toluene; ethanol / 11 h / Heating 4: sodium borohydride / methanol / 0.5 h / Ambient temperature 5: 95 percent / 85percent phosphoric acid / 12 h / 170 - 180 °C View Scheme

sodium acetate

1: sulfuric acid / 72 h / |Reflux 2: triphenylphosphine; di-isopropyl azodicarboxylate / tetrahydrofuran / 16 h / -10 - 20 °C 3: sodium hydride / tetrahydrofuran; mineral oil / 16 h / 0 - 20 °C / |Inert atmosphere 4: pyridine / dichloromethane / 16 h / 0 - 20 °C View Scheme