反应详情

An eggplant flask (50 mL) equipped with a reflux condenser was charged with 5-(benzoxazol-2-yl)-2-hydroxymethyl-1-(tetrahydropyran-4-yl)benzimidazole (see Working Example 13) (0.055 g, 0.16 mmol), oxalyl chloride (0.024 g, 0.19 mmol), and anhydrous dichloromethane (3 mL), and after the addition of anhydrous N,N-dimethylformamide (5 drops) at room temperature, this was refluxed for 3.5 hours. After cooling to room temperature, the solvent was distilled off under reduced pressure. To the yellow residue was added anhydrous tetrahydrofuran (5 mL) and anhydrous sodium iodide (0.036 g, 0.24 mmol), followed by a tetrahydrofuran solution of dimethylamine (2.0 M, 3 mL), and this was refluxed for 14 hours. After being allowed to cool to room temperature, the solvent was distilled off under reduced pressure. The yellow residue (0.70 g) was purified by silica gel column chromatography (silica gel: 2.6 g; MeOH/CHCl3=1/5) to yield the title compound (0.026 g, 43% yield) as a pale yellow powder.

1. customAn eggplant flask (50 mL) equipped with a reflux condenser
2. temperaturethis was refluxed for 3.5 hours
3. distillationthe solvent was distilled off under reduced pressure
4. temperaturethis was refluxed for 14 hours
5. temperatureto cool to room temperature
6. distillationthe solvent was distilled off under reduced pressure
7. customThe yellow residue (0.70 g) was purified by silica gel column chromatography (silica gel: 2.6 g; MeOH/CHCl3=1/5)