Table 3.

One-pot synthesis of benzimidazoles.

[a] Reaction conditions: substrate (1.0 mmol), NH₄CHO₂ (3.3 equiv.), Mont-K10 (300 mg), Pd/C (0.05 equiv. Pd), reflux, 1 h; then aldehyde (1 equiv.), 4 °C - rt, 16 h [b] Isolated yield after chromatography. [c] Isolated as a mixture of tautomers that equilibrate at elevated temperatures (see supporting information). [d] 2-nitrophenol was used as the substrate.