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 of copending U.S. Ser. No. 644,996) and 9 ml of methanol, and the mixture was stirred for 2 hours at room temperature, after which a 1% w/v aqueous solution of acetic acid was added and the mixture was neutralized with an aqueous solution of potassium carbonate. It was then extracted with ethyl acetate. The ethyl acetate extract was washed with water and dried over anhydrous sodium sulfate. The ethyl acetate was distilled from the extract under reduced pressure and the resulting residue was purified by silica gel column chromatography, using a 5:3 by volume mixture of hexane and ethyl acetate as eluent, to give the title compound, melting at 102°-118° C.

1. customprepared
2. extractionIt was then extracted with ethyl acetate
3. extractionThe ethyl acetate extract
4. washwas washed with water
5. dry with materialdried over anhydrous sodium sulfate
6. distillationThe ethyl acetate was distilled from the
7. extractionextract under reduced pressure
8. customthe resulting residue was purified by silica gel column chromatography
9. additionby volume mixture of hexane and ethyl acetate as eluent