反应详情

A stirred solution of 2-triethylstannyloxazole (Chem. Mater. 1994, 6, 1023) (1.5 g, 5.5 mmol) and methyl 3-[(dipropylamino)carbonyl]-5-iodobenzoate (1.8 g, 4.6 mmol) in dimethylformamide (12 mL) was degassed under reduced pressure for 15 min and purged with argon. Palladium(0)tetrakis(triphenylphosphine) (158 mg, 0.14 mmol) was added and the reaction mixture was degassed under reduced pressure for 15 min and then purged with argon. The reaction mixture was heated at reflux for 2 d, cooled to room temperature, diluted with ethyl acetate, washed with water (3×50 mL), dried (sodium sulfate), and concentrated under reduced pressure. Purification by flash column chromatography (silica, 1:1 ethyl acetate/hexanes) provided methyl 3-[(dipropylamino)carbonyl]-5-(1,3-oxazol-2-yl)benzoate (423 mg): 1H NMR (300 MHz, CDCl3) δ 8.73 (s, 1H), 8.23 (s, 1H), 8.11 (s, 1H), 7.76 (s, 1H), 7.28 (s, 1H), 3.97 (s, 3H), 3.49 (br s, 2H), 3.18 (br s, 2H), 1.72 (d, J=7 Hz, 2H), 1.55 (d, J=7 Hz, 2H), 1.00 (t, J=7 Hz, 3H), 0.75 (t, J=7 Hz, 3H).

1. custompurged with argon
2. customthe reaction mixture was degassed under reduced pressure for 15 min
3. custompurged with argon
4. temperatureThe reaction mixture was heated
5. temperatureat reflux for 2 d
6. additiondiluted with ethyl acetate
7. washwashed with water (3×50 mL)
8. dry with materialdried (sodium sulfate)
9. concentrationconcentrated under reduced pressure
10. customPurification by flash column chromatography (silica, 1:1 ethyl acetate/hexanes)