Dimethylformamide → HCID 21111268, compound

Participants

Reaction Conditions

Reaction Steps

5-Bromo-3-(2-chloro-benzyloxy)-pyridin-2-ylamine (4.50 g, 14.3 mmol), 4-carboxybenzeneboronic acid (2.62 g, 15.8 mmol), tetrakis(triphenylphosphine)palladium(0) (0.56 g, 0.5 mmol), potassium carbonate (6.90 g, 50 mmol), dimethylformamide (36 mL), and water (18 mL) were charged to a 250 mL three neck round bottom flask equipped with a thermometer, a reflux condenser and magnetic stirring. The mixture was purged with nitrogen and gradually heated from 82 to 93° C. over a period of 4 hr. Thin layer chromatography (ethyl acetate:hexane:acetic acid 4:6:0.5) showed product at Rf 0.3 and a few small impurities. The mixture was cooled to 45° C. The solids were collected by vacuum filtration, washed with 10 mL of ethanol:water 1:1 and discarded. The combined filtrate was diluted with 216 mL of water and 4 mL of 9 N potassium hydroxide solution (to pH 12-13), cooled in an ice bath and stirred for 30 minutes with 3 g of Celite and 3 g of Norit. The solids were collected by vacuum filtration through a pad of Celite and washed with 10 mL of water. The solids were discarded. The combined filtrate was cooled in an ice bath and acidified to pH 7 with acetic acid using a pH meter. The solids were collected by vacuum filtration, washed with 20 mL of ethanol-water 1:1 and dried under vacuum to give 2.7 g (53% yield) of 4-[6-amino-5-(2-chloro-benzyloxy)-pyridin-3-yl]-benzoic acid.

Provenance & Evidence