Eluents sodium sulfate/sulfuric acid

To which a solution of manganese sulfate (15 g), 3.1 g of chromium trioxide, 72 ml of water and 3.5 ml of sulfuric acid was added. After stirring for 3.5 hours at 3°C, extracted with diethyl ether. The organic layer was washed with water, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel using ethyl acetate-benzene (1 1) as eluent to give 2.35 g of the title compound. 

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