反应详情

A solution of LDA (2.86 mL, 5.14 mmol) in THF (2.5 mL) was transferred to a solution of 4-bromopyridine hydrochloride (500 mg, 2.57 mmol) in THF (5 mL) at −78° C. and stirred for 30 min. Zinc chloride (350 mg, 2.57 mmol) in THF (2.5 mL) was added to the above reaction mixture. A precipitate was formed and the mixture was allowed to warm to room temperature. Next, 1-bromo-4-nitrobenzene (1039 mg, 5.14 mmol) and tetrakis(triphenylphosphine)palladium(0) (149 mg, 0.129 mmol) were added, and the reaction mixture was heated to reflux for 3 hours and then cooled to room temperature. The resulting reaction mixture was diluted with saturated solution of ammonium chloride (25 mL) and extracted with EtOAc (2×25 mL). The combined organics were washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude material was purified by silica gel chromatography (40 g ISCO column, eluting with 0% to 50% EtOAc in CH2Cl2) to afford Intermediate 13A (300 mg, 1.023 mmol, 10.47% yield) as a pale yellow solid. MS (ES): m/z=280.9 [M+H]+. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.84 (s, 1 H) 7.87 (s, 1 H) 7.97 (d, J=5.29 Hz, 1 H) 8.41 (s, 1 H) 8.43 (s, 1 H) 8.57 (d, J=5.29 Hz, 1 H) 8.66 (s, 1 H).

1. customA precipitate was formed
2. temperaturethe reaction mixture was heated
3. temperatureto reflux for 3 hours
4. temperaturecooled to room temperature
5. customThe resulting reaction mixture
6. extractionextracted with EtOAc (2×25 mL)
7. washThe combined organics were washed with brine
8. dry with materialdried over anhydrous sodium sulfate
9. concentrationconcentrated under reduced pressure
10. customThe crude material was purified by silica gel chromatography (40 g ISCO column, eluting with 0% to 50% EtOAc in CH2Cl2)