反应详情

Ethyl 1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate (0.98 g, 4.00 mmol) prepared in the Step 38-1-5 was dissolved in methanol (100 ml), and acetic acid (1.00 ml) and a 37% formaldehyde aqueous solution (1.2 ml) were added thereto. Thereafter, sodium cyanoborohydride (0.57 g, 9.07 mmol) was added to the mixture, and the resulting mixture was stirred. After 30 minutes, the mixture was concentrated under a reduced pressure. Chloroform was added to the concentrate, and the resulting mixture was washed with a saturated sodium bicarbonate solution. The washed product was dried over anhydrous magnesium sulfate and concentrated. The concentrate was purified by silica gel column chromatography (chloroform:methanol=10:1) to give the title compound (958 mg, 92%) as a light-brown powder.

1. concentrationthe mixture was concentrated under a reduced pressure
2. additionChloroform was added to the concentrate
3. washthe resulting mixture was washed with a saturated sodium bicarbonate solution
4. dry with materialThe washed product was dried over anhydrous magnesium sulfate
5. concentrationconcentrated
6. customThe concentrate was purified by silica gel column chromatography (chloroform:methanol=10:1)