反应详情

Imidazole (0.1 g) and tert-butyldimethylsilyl chloride (0.08 g) are added to a solution of the object compound (0.036 g) of Example 6 in DMF (5 ml) at 40° C. and the mixture is stirred at the same temperature for 2 hours and then poured into a mixture of ethyl acetate (50 ml) and water (30 ml). The organic layer is separated, washed with brine, dried over magnesium sulfate and concentrated under reduced pressure. The residue is dissolved in a mixture of tetrahydrofuran (7 ml) and water (2 ml), and stirred at 25° C. for 4 hours in the presence of a trace of concentrated sulfuric acid. The reaction mixture is poured into a mixture of ethyl acetate (50 ml) and water (30 ml) and the organic layer is separated, washed with brine, dried over magnesium sulfate and concentrated under reduced pressure. Thus obtained residue is dissolved in ethyl acetate (12 ml) and m-chloroperbenzoic acid (0.3 g) is added thereto. The mixture is stirred at room temperature for 2 days and then poured into a mixture of ethyl acetate (50 ml), saturated sodium bicarbonate solution (20 ml) and dimethyl sulfide (0.15 ml) followed by stirring. The organic layer is separated, washed with brine, dried over magnesium sulfate and concentrated under reduced pressure. The residue is subjected to silica gel column chromatography (eluent: 15% ethyl acetate-85% hexane) to give 0.012 g of (3R,4R)-4-acetoxy-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-2-azetidinone.

1. customThe organic layer is separated
2. washwashed with brine
3. dry with materialdried over magnesium sulfate
4. concentrationconcentrated under reduced pressure
5. dissolutionThe residue is dissolved in a mixture of tetrahydrofuran (7 ml) and water (2 ml)
6. stirringstirred at 25° C. for 4 hours in the presence of a trace of concentrated sulfuric acid
7. additionThe reaction mixture is poured into a mixture of ethyl acetate (50 ml) and water (30 ml)
8. customthe organic layer is separated
9. washwashed with brine
10. dry with materialdried over magnesium sulfate
11. concentrationconcentrated under reduced pressure
12. dissolutionThus obtained residue is dissolved in ethyl acetate (12 ml)
13. additionm-chloroperbenzoic acid (0.3 g) is added
14. stirringThe mixture is stirred at room temperature for 2 days
15. additionpoured into a mixture of ethyl acetate (50 ml), saturated sodium bicarbonate solution (20 ml) and dimethyl sulfide (0.15 ml)
16. stirringby stirring
17. customThe organic layer is separated
18. washwashed with brine
19. dry with materialdried over magnesium sulfate
20. concentrationconcentrated under reduced pressure