Water → HCID 59547225, compound

Reaction equation

[CH3:1][C:2]1[Se:6][C:5]([C:7]([O:9][CH3:10])=[O:8])=[CH:4][CH:3]=1.[Se](=O)=[O:12].O>C(O)(=O)C>[CH:1]([C:2]1[Se:6][C:5]([C:7]([O:9][CH3:10])=[O:8])=[CH:4][CH:3]=1)=[O:12]

Participants

Procedure

To a solution of methyl 5-methylselenophene-2-carboxylate (5.0 g, 24.6 mmol) in acetic acid (30 mL) was added selenium dioxide (10.84 g, 98.4 mmol) at rt and the mixture was refluxed for 8 h. The cooled reaction mixture was poured into ice cooled water and stirred for 15 min. The solution was extracted with chloroform (3×100 mL) and the combined organic layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent. The residue was chromatographed over silica gel column using hexane-EtOAc (9:1) as eluents to give the product as pale yellow color solid (4.0 g, 75%), mp 63-65° C.; 1H NMR (400 MHz, CDCl3): δ 9.84 (1H, s, —CHO), 8.11 (1H, d, J=4.0 Hz, H-3), 7.99 (1H, d, J=4.0 Hz, H-4), 3.92 (3H, s, —COOCH3).