反应详情

温度

-30 °C

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of 5-(2-methyl-[1,3]dioxolan-2-yl)-pentanoic acid (4.78 g, 25.40 mmol) in THF (165 mL) at −30° C. was treated sequentially with Et3N (7.50 mL, 53.33 mmol) followed by isobutyl chloroformate (3.81 mL, 27.94 mmol). After stirring for 1 h at −30° C., serine methylester hydrochloride (4.43 g, 37.94 mmol) was added and the reaction mixture was allowed to warm gradually to rt over 3 h and stirred for an additional 16 h at rt. The resulting suspension was filtered, the solid washed with THF and the filtrate was concentrated under reduced pressure. Purification of the residue by FC (9:1:0→0:9:1 hept-EA-MeOH) gave the title compound as a colorless oil. TLC: rf (1000:50:4 CH2Cl2-MeOH—NH3)=0.1. LC-MS-conditions 02: tR=0.63 min [M+H]+=290.25.

1. temperatureto warm gradually to rt over 3 h
2. stirringstirred for an additional 16 h at rt
3. filtrationThe resulting suspension was filtered
4. washthe solid washed with THF
5. concentrationthe filtrate was concentrated under reduced pressure
6. customPurification of the residue by FC (9:1:0→0:9:1 hept-EA-MeOH)