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温度

0 °C

((2R)-2-amino-N-{6-[(2,2-dimethyl-2,3-dihydro-1-benzofuran-4-yl)oxy]-3-pyridinyl}butanamide) (Intermediate 209, 10 mg, 0.029 mmol) was dissolved in dry dichloromethane (1 ml). The reaction mixture was cooled down in an ice bath. Triethylamine (0.024 ml, 0.176 mmol) was added at 0° C. Then 0.5 ml of a solution of triphosgene in dry dichloromethane (4.78 mg, 0.016 mmol in 0.5 ml) was added dropwise. The reaction mixture was stirred under argon during 20 min at 0° C. A saturated aqueous solution of NaHCO3 was added (3 ml). The aqueous layer was extracted with dichloromethane 4 times (4×4 mL). Combined organic layers were dried over Na2SO4 and evaporated. the residue was purified by flash chromatography (Companion system) on silica gel using a 4 g silica cartridge and cyclohexane/ethyl acetate from 100:0 to 60:40 as eluents affording the title compound (7 mg).

1. temperatureThe reaction mixture was cooled down in an ice bath
2. extractionThe aqueous layer was extracted with dichloromethane 4 times (4×4 mL)
3. dry with materialCombined organic layers were dried over Na2SO4
4. customevaporated
5. customthe residue was purified by flash chromatography (Companion system) on silica gel using a 4 g silica cartridge and cyclohexane/ethyl acetate from 100:0 to 60:40 as eluents