反应详情

A suspension of 2-n-butyl-1-(2-chlorophenyl)methyl-6-hydroxymethyl-1H-benzimidazole (1 g, 3.04 mmol, prepared in Example 9(i)), toluene (500 mL) and activated manganese dioxide (4 g) was refluxed with a Dean-Stark water separator for 4 hours. The mixture was filtered hot, concentrated and the crude product was treated with celite in methylene chloride to afford, after concentration, a residue that crystallized. Recrystallization from hexane gave 0.65 g (66%) of 2-n-butyl-1-{(2-chlorophenyl)methyl}-1H-benzimidazole-7-carboxaldehyde; mp 113.5°-115° C.

1. filtrationThe mixture was filtered hot
2. concentrationconcentrated
3. additionthe crude product was treated with celite in methylene chloride
4. customto afford
5. concentrationafter concentration
6. customa residue that crystallized
7. customRecrystallization from hexane