反应详情

A portion of 2-iodo-4-(5-methylthiophen-2-yl)-1H-imidazole 3 (940 mg, 3.25 mmol), thiophene-2,5-diboronic acid (250 mg, 1.46 mmol), Na2CO3 (780 mg, 7.40 mmol) in H2O (5 mL) and DMF (40 mL) was degassed (N2 bubbling). Pd(PPh3)4 (85 mg) was added and the mixture was heated to reflux for 3 h. The mixture was allowed to cool to room temperature and concentrated. The mixture was diluted with EtOAc and H2O and the organic phase was separated. The aqueous phase was re-extracted (EtOAc) and the combined organics were washed (saturated aqueous NaCl), dried (MgSO4), filtered and concentrated to give a residue. The residue was purified by flash chromatography (EtOAc/hexanes 35:65 then 50:50 then 75:25) to give 2,5-bis(4-(5-methylthiophen-2-yl)-1H-imidazol-2-yl)thiophene 4 (1.65 g, 27%) as a pale brown solid. 1H NMR [(CD3)2SO, 400 MHz] δ2.44 (s, 6H), 6.75 (s, 2H), 7.11 (d, J=3.0 Hz, 2H), 7.51 (br s, 4H), 12.65-12.85 (br s, 2H); HRMS (EI) m/z 408.0539 C20H16N4S3 [M]+. requires 408.0532.

1. temperaturethe mixture was heated
2. temperatureto reflux for 3 h
3. concentrationconcentrated
4. additionThe mixture was diluted with EtOAc and H2O
5. customthe organic phase was separated
6. extractionThe aqueous phase was re-extracted (EtOAc)
7. washthe combined organics were washed (saturated aqueous NaCl)
8. dry with materialdried (MgSO4)
9. filtrationfiltered
10. concentrationconcentrated
11. customto give a residue
12. customThe residue was purified by flash chromatography (EtOAc/hexanes 35:65