反应详情

温度

75 °C

To a mixture of 4-amino-3-chlorophenylboronic acid pinacol ester (0.110 g, 0.434 mmol), 2-bromopyrazine (0.090 g, 0.56 mmol), 1,1′-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) DCM complex (24 mg, 0.029 mmol) was added anhydrous DME (3.0 mL) followed by 2M aqueous sodium carbonate (0.53 mL, 1.06 mmol). The microwave vial was heated at 75° C. for 40 minutes under microwave irradiation. Further catalyst (0.012 g) was added and the vial was heated at 90° C. for 25 minutes under microwave irradiation. Further 2-bromopyrazine (0.060 g), catalyst (12 mg) and 2M aqueous sodium carbonate (0.25 mL) were added and the reaction mixture was heated at 90° C. for an additional 30 minutes under microwave irradiation. The reaction was partitioned between ethyl acetate (60 mL) and a saturated aqueous NaHCO3 solution (15 mL). The organic layer was washed with a saturated aqueous NaHCO3 solution (2×15 mL), dried (Na2SO4) and concentrated in vacuo. The residue was purified using preparative TLC eluting with 7% ethyl acetate in CH2Cl2. The product band was recovered and stirred with 2% MeOH in ethyl acetate/CH2Cl2 (v/v; 1:10) (20 mL). The silica was removed by filtration, washed with ethyl acetate/CH2Cl2 (v/v; 1:5) (2×5 mL) and acetone (3×4 mL) to give the title compound as an off-white solid (0.039 g, 44%). 1H-NMR (500 MHz, DMSO-d6) 5.86 (s, 2H), 6.89 (d, J=8.5, 1H), 7.85 (dd, J=2.1, 8.5 Hz, 1H), 8.02 (d, J=2.1 Hz, 1H), 8.44 (d, J=2.5 Hz, 1H), 8.57 (dd, J=1.6, 2.5 Hz, 1H), 9.12 (d, J=1.5 Hz, 1H).

1. temperaturethe vial was heated at 90° C. for 25 minutes under microwave irradiation
2. temperaturethe reaction mixture was heated at 90° C. for an additional 30 minutes under microwave irradiation
3. customThe reaction was partitioned between ethyl acetate (60 mL)
4. washThe organic layer was washed with a saturated aqueous NaHCO3 solution (2×15 mL)
5. dry with materialdried (Na2SO4)
6. concentrationconcentrated in vacuo
7. customThe residue was purified
8. washeluting with 7% ethyl acetate in CH2Cl2
9. customThe product band was recovered
10. customThe silica was removed by filtration
11. washwashed with ethyl acetate/CH2Cl2 (v/v; 1:5) (2×5 mL) and acetone (3×4 mL)