反应详情

温度

90 °C

2,6-Dichloronicotinic acid (1.20 g, 6.25 mmol), 3-(tert-butoxycarbonyl)benzene boronic acid (2.08 g, 9.10 mmol), potassium carbonate (2.60 g, 18.8 mmol), tetrakis(triphenylphosphine)palladium (0.72 g, 0.62 mmol), degassed 1,2-dimethoxyethane (30 mL) and water (0.5 mL) were combined under an argon atmosphere and the mixture heated at 90° C. overnight. The reaction mixture was then cooled to room temperature, diluted with water (100 mL) and extracted with ethyl acetate (2×150 mL). The aqueous layer was acidified to pH 3-4 using 2N HCl solution and extracted with ethyl acetate (2×200 mL). The combined organic portions were dried over anhydrous sodium sulfate and concentrated. The residue was purified by column chromatography (silica gel, 20% methanol/dichloromethane) and the product containing fractions concentrated to give a solid, which was triturated with 2:1 heptane/ethyl acetate to give pure 6-(3-(tert-butoxycarbonyl)phenyl)-2-chloronicotinic acid (1.4 g, 67%) as an off-white foam. 1H NMR (400 MHz, CD3OD) δ ppm 8.64 (s, 1H), 8.34 (d, 1H), 8.29 (d, 1H), 8.04 (d, 1H), 7.95 (d, 1H), 7.59 (t, 1H), 1.60 (s, 9H); m/z 334 [M+H].

1. temperatureThe reaction mixture was then cooled to room temperature
2. extractionextracted with ethyl acetate (2×150 mL)
3. extractionextracted with ethyl acetate (2×200 mL)
4. dry with materialThe combined organic portions were dried over anhydrous sodium sulfate
5. concentrationconcentrated
6. customThe residue was purified by column chromatography (silica gel, 20% methanol/dichloromethane)
7. additionthe product containing fractions
8. concentrationconcentrated
9. customto give a solid, which
10. customwas triturated with 2:1 heptane/ethyl acetate