Reaction detail

Temperature

50 °C

3.48 g (20 mmol) of 4-phenylcyclohexanone in 3.3 ml of ethanol are treated with 3.3 ml of triethyl orthoformate and 2 drops of boron trifluoride etherate and warmed at 50° C. for 30 min. After addition of 2.01 g (10mmol) of 2-ethyl-3-bromo-4-aminopyridine the reaction mixture is heated at 135°-140° C. for 3.5-4 hours with simultaneous removal of the low-boiling components by distillation. It is then cooled, 40 ml of dichloroethane, 3.18 g (15 mmol) of sodium triacetoxyborohydride and 0.57 ml (10 mmol) of glacial acetic acid are added, and it is heated at 50°-60° C. for 3 hours; the reaction mixture is then cooled, saturated aqueous sodium hydrogen carbonate solution is added, the 1,2-dichloroethane is evaporated and the reaction product is extracted from the aqueous phase using ethyl acetate. Purification is carried out by column chromatography. Yield: 1.46 g (41%); RF =0.59 (ethyl acetate)

1. temperatureis heated at 135°-140° C. for 3.5-4 hours with simultaneous removal of the low-boiling components by distillation
2. temperatureIt is then cooled
3. temperatureit is heated at 50°-60° C. for 3 hours
4. temperaturethe reaction mixture is then cooled
5. customthe 1,2-dichloroethane is evaporated
6. extractionthe reaction product is extracted from the aqueous phase
7. customPurification