Sodium Thiosulfate → Methyl 5-formyl-4-(imidazo[1,2-b]pyridazin-3-yl)thiophene-2-carboxylate

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Reaction Steps

To a stirred solution of methyl 5-ethenyl-4-(imidazo[1,2-b]pyridazin-3-yl)thiophene-2-carboxylate (160 mg, 0.56 mmol) in THF (1.9 mL) and water (0.95 mL) were added OsO4 (4% in water, 0.36 mL, 0.056 mmol) and NMO (79 mg, 0.67 mmol). The reaction mixture was left to stir for 5 h, treated with additional 0504 (4% in water, 0.36 mL, 0.056 mmol) and NMO (79 mg, 0.67 mmol), and left to stir overnight. Additional OsO4 (4% in water, 0.36 mL, 0.056 mmol) and NMO (79 mg, 0.67 mmol) were added and the resultant solution was left to stir for 1 d, treated with aqueous sodium thiosulfate, and left to stir for 2 h. The mixture was extracted with dichloromethane (×3). The combined organics were dried (sodium sulfate), and concentrated. The residue was dissolved in THF (6 mL) and water (3 mL), and treated with sodium periodate (143 mg, 0.67 mmol). The mixture was left to stir overnight, diluted with water, and extracted with dichloromethane (×3). The combined organics were dried (sodium sulfate), concentrated, and purified by flash chromatography to afford the title compound as a yellow solid. LRMS (APCI) calc'd for (C13H10N3O3S) [M+H]+, 288.0. found 288.0.

Provenance & Evidence