反应详情

Palladium catalyst Pd(PPh3)4 (693 mg, 0.6 mmol) and freshly prepared aqueous sodium hydroxide (3.2 g in 29 mL of water) were added to a mixture of 4-(4,4,5,5-tetramethyl[1,3,2]-dioxaborolan-2-yl)-1H-indole (4.9 g, 20.2 mmol) and 5-bromonicotinic acid (4.04 g, 20 mmol) in THF (70 mL). The system was degassed and then purged three times with nitrogen. The mixture was refluxed under nitrogen for 6 hours. It was then cooled to room temperature and ethyl acetate (400 mL) added. The organic layer was separated and washed twice with 2N NaOH solution. The aqueous layer and hydroxide washes were combined, washed with dichloromethane and then acidified with 6N HCl. The resulting precipitate was collected by vacuum filtration, washed with water and dried to give 2.3 g (48%) 5-(1H-indol-4-yl)-nicotinic acid.

1. customThe system was degassed
2. custompurged three times with nitrogen
3. temperatureThe mixture was refluxed under nitrogen for 6 hours
4. additionethyl acetate (400 mL) added
5. customThe organic layer was separated
6. washwashed twice with 2N NaOH solution
7. washwashed with dichloromethane
8. filtrationThe resulting precipitate was collected by vacuum filtration
9. washwashed with water
10. customdried