Sodium Hydroxide → 5-(1H-indol-4-yl)-nicotinic acid

Participants

Reaction Steps

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.

Provenance & Evidence