Formic Acid → 2,4'-Bipyridine

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.).

1. temperaturethe mixture was refluxed for 1 hour
2. customthe reaction at 100° C. for 8 hours
3. customAfter completion of the reaction
4. temperaturethis was cooled to room temperature
5. extractionextracted three times with 200 ml of toluene
6. concentrationThe organic layer was concentrated
7. distillationpurified by distillation under a reduced pressure

ORD record

ord-a2e23513292043feb7abcfbb506a170f

Source dataset

uspto-grants-2010_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07723522B2