反应详情

Ethyl 1-cyclopentyl-2-(4-nitrophenyl)benzimidazole-5-carboxylate (12 g) obtained in Example 21 was dissolved in tetrahydrofuran (200 ml) and ethyl alcohol (50 ml), 7.5% palladium carbon (50% wet, 1 g) was added. The mixture was hydrogenated for 1 hr at atmospheric pressure. The catalyst was filtered off and the filtrate was concentrated under reduced pressure. Tetrahydrofuran was added to the residue to allow crystallization and the crystals were collected by filtration to give the title compound (11 g, yield 98%).

1. filtrationThe catalyst was filtered off
2. concentrationthe filtrate was concentrated under reduced pressure
3. additionTetrahydrofuran was added to the residue
4. customcrystallization
5. filtrationthe crystals were collected by filtration