85 mg (0.982 mmol) of manganese dioxide is added at room temperature to a solution of (4-(4-methylpiperazine-1-yl)-2-(tetrahydro-2H-pyran-4-ylamino)phenyl)methano 1 (100 mg, 0.327 mmol) in a mixture of ethyl acetate (10 ml) and dichloromethane (9 ml). The reaction mixture is placed in an ultrasonic bath for 5 hours. The reaction mixture is filtered, the solvents are evaporated and the crude product is purified by chromatography to yield 50.0 mg (yield=50.3%) of (4-(4-methylpiperazine-1-yl)-2-(tetrahydro-2H-pyran-4-ylamino)benzaldehyde in the form of a white solid.
