反应详情

A solution of (S)-1-(tert-butoxycarbonyl)azetidine-2-carboxylic acid (1.80 g, 8.95 mmol) in tetrahydrofuran (90.0 mL) was cooled to 0° C., and isobutyl chloroformate (1.30 mL, 9.85 mmol) and triethylamine (1.50 mL, 10.7 mmol) were added. After stirring for 1 hour at room temperature, ammonium salt was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was dissolved in acetonitrile (90.0 mL), and trimethylsilyldiazomethane (13.5 mL, 26.8 mmol) was added. After stirring for 7 hours at room temperature, to the mixture were added saturated sodium bicarbonate water and ethyl acetate. The aqueous layer was extracted with ethyl acetate, and the organic layer was washed with water and brine, and then dried over sodium sulfate, and concentrated under reduced pressure. The obtained residue was purified with silica gel column (hexane/ethyl acetate=90/10 to 75/25) to give the title compound (1.40 g, 6.22 mmol, 69%).

1. filtrationammonium salt was filtered off
2. concentrationthe filtrate was concentrated under reduced pressure
3. dissolutionThe obtained residue was dissolved in acetonitrile (90.0 mL)
4. stirringAfter stirring for 7 hours at room temperature, to the mixture
5. extractionThe aqueous layer was extracted with ethyl acetate
6. washthe organic layer was washed with water and brine
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated under reduced pressure
9. customThe obtained residue was purified with silica gel column (hexane/ethyl acetate=90/10 to 75/25)