Formic Acid → 2,4'-Bipyridine

Participants

Reaction Steps

15.0 g (92 mmol) of 1,1,3,3-tetramethoxypropane and 20.5 g (119 mmol) of 1,3-di(n-butyl)urea were dissolved in 20 ml of 2-propanol, 13.0 g (125 mmol) of 35% hydrochloric acid was added thereto, and the mixture was refluxed for 1 hour. The reaction solution was cooled to room temperature, and 10.0 g (83 mmol) of 4-acetylpyridine and 7.1 g (89.8 mmol) of pyridine were added thereto. After 30 minutes of stirring at room temperature, 19 ml (416 mmol) of formic acid and 31.5 g (500 mmol) of ammonium formate were added to the reaction solution to carry out the reaction at 100° C. for 8 hours. After completion of the reaction, this was cooled to room temperature, neutralized with 200 g (1.2 mol) of 25% sodium hydroxide aqueous solution and then extracted three times with 200 ml of toluene. The organic layer was concentrated and then purified by distillation under a reduced pressure to obtain 9.9 g (yield 76.5%) of the title compound (purity 99.9%, melting point 55-57° C.).

Provenance & Evidence