反应详情

5.0 ml of methylmagnesium bromide were added dropwise to a solution of 0.61 g of 2-formylbenzothiazole [prepared as described in step (a) above] which was cooled in an acetone-dry ice bath. The reaction vessel was transferred to an ice-water bath and the reaction mixture was stirred for 3.5 hours. At the end of this time, a saturated aqueous ammonium chloride solution was added to the reaction mixture and the resulting mixture was extracted with ethyl acetate. The resulting extract was washed with a saturated aqueous sodium chloride solution and then dried over anhydrous sodium sulfate. The solvent was then removed by evaporation under reduced pressure and the resulting residue was purified by column chromatography through silica gel using a 4:1 by volume mixture of hexane and ethyl acetate as the eluent, to give 0.44 g (yield 66%) of the title compound as a solid having a melting point of 59° to 60° C.

1. temperaturewas cooled in an acetone-dry ice bath
2. customThe reaction vessel was transferred to an ice-water bath
3. extractionthe resulting mixture was extracted with ethyl acetate
4. extractionThe resulting extract
5. washwas washed with a saturated aqueous sodium chloride solution
6. dry with materialdried over anhydrous sodium sulfate
7. customThe solvent was then removed by evaporation under reduced pressure
8. customthe resulting residue was purified by column chromatography through silica gel using a 4:1
9. additionby volume mixture of hexane and ethyl acetate as the eluent