反应详情

To a stirred solution of 2,6-dichloro-5-nitro-1H-benzoimidazole (5.43 g, 23.4 mmol), diisopropylethylamine (12.2 mL, 70.2 mmol), and THF (120 mL) was added portionwise 1-chloromethoxy-2-methoxy-ethane (3.30 mL, 28.1 mmol). The reaction mixture was stirred for 2.5 h and concentrated. Water (50 mL) was added to the residue, the mixture was extracted with EtOAc (3×125 mL). The combined organic layers were washed with brine (100 mL), dried, filtered, and concentrated under reduced pressure. The residue was purified (FCC) (20-55% EtOAc/hexanes) to yield the titled compound (6.23 g, 83% yield) as a 1:1 mixture of regioisomers. MS (ESI/CI): mass calcd. for C11H11Cl2N3O4, 319.0; m/z found, 320.0 [M+H]+. 1H NMR (400 MHz, CDCl3): 8.24 (s, 1H), 8.16 (s, 1H), 7.83 (s, 1H), 7.69 (s, 1H), 5.71 (s, 2H), 5.68 (s, 2H), 3.72-3.64 (m, 4H), 3.57-3.50 (m, 4H), 3.35 (s, 3H), 3.35 (s, 3H).

1. concentrationconcentrated
2. additionWater (50 mL) was added to the residue
3. extractionthe mixture was extracted with EtOAc (3×125 mL)
4. washThe combined organic layers were washed with brine (100 mL)
5. customdried
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified (FCC) (20-55% EtOAc/hexanes)