||With manganese(IV) oxide; In dichloromethane; N,N-dimethyl-formamide; at 20℃; for 4h;
||To a solution of <strong>[65658-13-1](1H-benzo[d]imidazol-4-yl)methanol</strong> (0.356 g, 2.40 mmol) in CH2Cl2/DMF (1:1, 50 mL) was added activated MnO2 (2.086 g, 24.00 mmol). The reaction was stirred at room temperature until TLC showed full conversion (4 hours). The reaction was filtered through a tight-packed pad of Celite and the pad was washed with CH2Cl2 (2 × 15 mL). The filtrate was evaporated and the solids were recrystallized from EtOAc/heptanes to give the title compound 4 (0.277 g, 79%) as pale yellow crystals. mp. 163 - 164 C. 1H NMR (300 MHz, DMSO-d6) δ 10.24 (s, 1H), 8.33 (s, 1H), 8.00 (dd, J = 8.0, 1.0 Hz, 1H), 7.83 (dd, J = 7.4, 1.0 Hz, 1H), 7.40 (dd, J = 8.0, 7.4 Hz,, 1H). 13C NMR (75 MHz, DMSO) δ 191.7, 144.2, 142.5, 127.0, 124.6, 122.2, 121.4
||With Dess-Martin periodane; In dichloromethane; at 20℃; for 12h;
||To a stirred solution of lH-l,3-benzodiazol-4-ylmethanol (1.20 g, 8.10 mmol, 1.00 equiv) in DCM (25.00 mL) was added Dess-Martin (6870.32 mg, 16.20 mmol, 2.00 equiv) at room temperature. After stirring for 12 hours at room temperature, saturated sodium thiosulfate solution (100 mL) was added. The mixture was extracted with DCM and the combined organic layers were washed saturated sodium chloride aqueous solution, dried over anhydrous sodium sulfate, fdtered and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, eluent: petroleum ether/ethyl acetate 42:58) to give 1H-1,3- benzodiazole-4-carbaldehyde (400 mg, 33.8%) as a white solid.
||With pyridine-SO3 complex; N-ethyl-N,N-diisopropylamine; In dimethyl sulfoxide; at 20℃;
||C. lH-Benzo[d]imidazole-4-carbaldehyde.; (lH-Benzo[d]imidazol-4- yl)methanol (550 mg, 3.72 mmol) was dissolved in dimethylsulfoxide (30 mL). Diisopropylethylamine (1.9 mL, 1 1.1 mmol) and sulfurtrioxide complex of pyridine (1.77 g, 1 1.1 mmol) was added and the solution allowed to stir overnight at room temperature.Poured reaction into water (50 mL) and extracted with ethyl acetate (3x150 mL), dried with sodium sulfate, and concentrated under reduced pressure to give a white solid (100 mg, 18%). MS (ESI) m/z 147.0 [M+l]+.