反应详情

A solution of 9.24 g (33.4 mmol) of 2-t-butyl-5-[(E)-2-ethoxycarbonylethenyl]-1-nitrobenzene [prepared as described in step (ii) above] in 200 ml of tetrahydrofuran was cooled to -70° C. in a dry ice-acetone bath, and 100 ml (100 mmol) of a 1 M solution of diisobutylaluminum hydride in tetrahydrofuran were added dropwise thereto over a period of 45 minutes. The resulting mixture was then stirred for a further 30 minutes. At the end of this time, the reaction temperature was allowed to rise to 0° C., and the reaction was quenched by adding dropwise a mixture of 4 ml of methanol and 20 ml of tetrahydrofuran. The reaction mixture was then poured into 2 N aqueous hydrochloric acid-ice, after which it was extracted with ethyl acetate. The extract was washed with water and with a saturated aqueous solution of sodium chloride, in that order, after which it was dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through 300 g of silica gel, using a 2:1 by volume mixture of hexane and ethyl acetate as the eluent, to give 7.06 g (yield 90%) of the title compound as an oily substance.

1. customto rise to 0° C.
2. customthe reaction was quenched
3. additionby adding dropwise
4. additiona mixture of 4 ml of methanol and 20 ml of tetrahydrofuran
5. additionThe reaction mixture was then poured into 2 N aqueous hydrochloric acid-ice
6. extractionafter which it was extracted with ethyl acetate
7. washThe extract was washed with water and with a saturated aqueous solution of sodium chloride, in that order
8. dry with materialafter which it was dried over anhydrous sodium sulfate
9. customThe solvent was removed by distillation under reduced pressure
10. customthe resulting residue was purified by column chromatography through 300 g of silica gel
11. additionby volume mixture of hexane and ethyl acetate as the eluent