反应详情

450 mg of sodium borohydride were added to a mixture of 278 mg of 5-[4-(6-hydroxy-2,5,7,8-tetramethyl-4-oxochroman-2-ylmethoxy)benzyl]thiazolidine-2,4-dione (prepared as described in Example 22) and 9 ml of methanol, and the resulting mixture was stirred at room temperature for 2 hours. Then, a 1% w/v aqueous solution of acetic acid was added to the reaction mixture, and the mixture was neutralized with an aqueous solution of potassium carbonate and extracted with ethyl acetate. The ethyl acetate solution was washed with water and dried over anhydrous sodium sulfate. Ethyl acetate was distilled off from the mixture under reduced pressure, and the resulting residue was subjected to silica gel column chromatography, eluted with a 5:3 by volume mixture of hexane and ethyl acetate, to yield 5-[4-(4,6-dihydroxy-2,5,7,8-tetramethylchroman-2-ylmethoxy)benzyl]thiazolidine-2,4-dione. Its melting point was 102°-118° C.

1. extractionextracted with ethyl acetate
2. washThe ethyl acetate solution was washed with water
3. dry with materialdried over anhydrous sodium sulfate
4. distillationEthyl acetate was distilled off from the mixture under reduced pressure
5. washeluted with a 5:3 by volume mixture of hexane and ethyl acetate