反应详情

温度

0 °C

To a solution of 2-bromopyridine (14 g, 88.6 mmol) in anhydrous ether (300 mL) cooled at −78° C. was slowly added a solution of 2.5 M butyl lithium (36 mL). After the addition, stirring was continued at −78° C. for 1 hour. To it was slowly added a solution of 1,4-cyclohexanedione mono-ethylene ketal (15 g, 96 mmol) in anhydrous ether (300 mL). When the addition was complete, the mixture was allowed to warm to 0° C. and stirring was continued for 1 hour. The reaction was quenched by the addition of an aqueous solution (100 mL) of ammonium chloride (4.5 g). The organic phase was separated and the aqueous phase was extracted with methylene chloride 4 times. The combined organic phases were dried over MgSO4 and concentrated. Crystallization from EtOAc provided 7 g of the desired product. The mother liquid was purified on silica gel eluting with 10% MeOH/EtOAc to give 3 g of the desired product. MS calculated (M+H)+ 236, found 236.0.

1. additionAfter the addition
2. additionWhen the addition
3. stirringstirring
4. waitwas continued for 1 hour
5. customThe reaction was quenched by the addition of an aqueous solution (100 mL) of ammonium chloride (4.5 g)
6. customThe organic phase was separated
7. extractionthe aqueous phase was extracted with methylene chloride 4 times
8. dry with materialThe combined organic phases were dried over MgSO4
9. concentrationconcentrated
10. customCrystallization from EtOAc