反应详情

A mixture of trans-4-(2-cyanoiminoimidazolidin-1-yl)-3,4-dihydro-3-hydroxy-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile (0.62 g) and acetic anhydride (0.47 ml) in dry pyridine (3.1 ml) was stirred at room temperature for 3 days. The mixture was diluted with ethyl acetate (30 ml) and washed with 5% hydrochloric acid (20 ml×2), brine (20 ml), saturated aqueous sodium bicarbonate (20 ml) and brine (20 ml), successively. The organic layer was dried over anhydrous magnesium sulfate and evaporated in vacuo. The residue was subjected to column chromatography on silica gel (50 g) and eluted with a mixture of chloroform and methanol (50:1). The fractions containing the object compound were combined and concentrated under reduced pressure. The residue was recrystallized from a mixture of dichloromethane and n-hexane to give trans-3-acetoxy-4-(2-cyanoiminoimidazolidin-1-yl)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile (0.44 g).

1. washwashed with 5% hydrochloric acid (20 ml×2), brine (20 ml), saturated aqueous sodium bicarbonate (20 ml) and brine (20 ml)
2. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
3. customevaporated in vacuo
4. washeluted with a mixture of chloroform and methanol (50:1)
5. additionThe fractions containing the object compound
6. concentrationconcentrated under reduced pressure
7. customThe residue was recrystallized from a mixture of dichloromethane and n-hexane