反应详情

38.98 g (596 mmol) of zinc dust were added to a solution of 13.24 g (59.6 mmol) of 2-t-butyl-5-carbamoyl-1-nitrobenzene [prepared as described in step (i) above] in 150 ml of methanol, and then 13 ml of acetic acid were added dropwise over a period of 10 minutes, whilst ice-cooling. The resulting mixture was then stirred at room temperature for 2 hours and then at 50° C. for 30 minutes. At the end of this time, the reaction mixture was diluted with ethyl acetate and filtered using a Celite (trade mark) filter aid. The filtrate was concentrated by evaporation under reduced pressure and the concentrate was dissolved in ethyl acetate. The resulting solution was washed with a saturated aqueous solution of ammonium chloride, with water and with a saturated aqueous solution of sodium chloride, in that order, after which it was dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting residue was crystallized from a mixture of ethyl acetate and hexane, to give 8.94 g (yield 78%) of the title compound, melting at 140.5-142° C. (from ethyl acetate-hexane).

1. temperaturecooling
2. waitat 50° C. for 30 minutes
3. filtrationfiltered
4. filtrationfilter aid
5. concentrationThe filtrate was concentrated by evaporation under reduced pressure
6. dissolutionthe concentrate was dissolved in ethyl acetate
7. washThe resulting solution was washed with a saturated aqueous solution of ammonium chloride, with water and with a saturated aqueous solution of sodium chloride, in that order
8. dry with materialafter which it was dried over anhydrous magnesium sulfate
9. customThe solvent was removed by distillation under reduced pressure
10. customthe resulting residue was crystallized from a mixture of ethyl acetate and hexane