Synthesis of a ruthenium complex based on 2,6-bis[1-(pyridin-2-yl)-1H-benzo[d]imidazol-2-yl]pyridine and catalytic oxidation of (1H-benzo[d]-imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehyde with H2O2

Article abstract of DOI:10.3184/174751917X14858862342106

2,6-Bis[1-(pyridin-2-yl)-1H-benzo[d]-imidazol-2-yl]pyridine (bpbp), which has been synthesised by intramolecular thermocyclisation of N²,N⁶-bis[2-(pyridin-2-ylamino)phenyl]pyridine-2,6-dicarboxamide, reacts with sodium pyridine-2,6-dicarboxylate (pydic) and RuCl₃ to give [Ru(bpbp)(pydic)] which can catalyse the oxidation of (1H-benzo[d]imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehyde by H₂O₂. The optimal reaction conditions were: molar ratios of catalyst to substrate to H₂O₂ set at 1 : 1000 : 3000; reaction temperature 50 °C; reaction time 5 h. The yield of (1H-benzo[d]imidazol-2-yl) methanol was 70%.