反应详情

温度

90 °C

2-Chloro-6-(dimethylamino)isonicotinic acid (450 mg, 2.24 mmol), 4-(tert-butoxycarbonyl)benzene boronic acid (648 mg, 2.92 mmol), 1,4-dioxane (7.5 mL) and sodium carbonate (713 mg, 6.73 mmol) dissolved in water (3.36 mL) were placed in a flask and the mixture bubbled with nitrogen while stirring for 10 min. Palladium(II) acetate (20 mg, 0.09 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (75 mg, 0.18 mmol) were then added together and the vessel flushed with nitrogen, sealed, and heated at 90° C. for 5 h. The mixture was then cooled to room temperature, diluted with ethyl acetate (50 mL), acidified to pH 2 with 1.5 N HCl and filtered through a pad of celite. The layers were separated and the aqueous portion extracted with ethyl acetate (2×50 mL). The combined organic portions were treated with anhydrous sodium sulfate and decolorizing charcoal and stirred for 30 min before filtering. The solution was concentrated to dryness and the residue purified by trituration with a mixture of methyl tert-butyl ether (5 mL) and heptane (100 mL). The solids were collected by filtration and dried to give 2-(4-(tert-butoxycarbonyl)phenyl)-6-(dimethylamino)isonicotinic acid (502 mg, 65%) as a pale yellow powder. m/z: 343+ [M+H]; 341− [M−H]; 1H NMR (400 MHz, CDCl3) δ ppm 8.12-8.21 (m, 2H), 8.04-8.11 (m, 2H), 7.67 (s, 1H), 7.16 (s, 1H), 3.23 (s, 6H), 1.64 (s, 9H).

1. customwere placed in a flask
2. customthe mixture bubbled with nitrogen
3. customthe vessel flushed with nitrogen
4. customsealed
5. temperatureThe mixture was then cooled to room temperature
6. additiondiluted with ethyl acetate (50 mL)
7. filtrationfiltered through a pad of celite
8. customThe layers were separated
9. extractionthe aqueous portion extracted with ethyl acetate (2×50 mL)
10. additionThe combined organic portions were treated with anhydrous sodium sulfate
11. stirringstirred for 30 min
12. filtrationbefore filtering
13. concentrationThe solution was concentrated to dryness
14. customthe residue purified by trituration with a mixture of methyl tert-butyl ether (5 mL) and heptane (100 mL)
15. filtrationThe solids were collected by filtration
16. customdried