反应详情

温度

20 °C

To a solution of (R)-2-methyl-azetidine-1,2-dicarboxylic acid 1-tert-butyl ester, Intermediate 33 (13 g, 1 eq.) in 300 mL of dry DCM under nitrogen was added dropwise a solution of 1-chloro-N,N,2-trimethylpropenylamine (16 mL, 2 eq.) in 50 mL of DCM. The solution was stirred at 20° C. for 30 min, then cooled to −5° C. A solution of 4-(3-chloro-benzylamino)-butyric acid methyl ester hydrochloride, Intermediate 80 (18.5 g, 1.1 eq.) and TEA (25 mL, 3 eq.) in 200 mL of DCM was added slowly to the previous mixture. The reaction was stirred at 20° C. for 2.5 h. The mixture was added to 500 mL of a saturated aqueous solution of NaHCO3. The crude was extracted three times with DCM. The organic layers were combined, washed with brine, dried over MgSO4, filtered, concentrated under reduced pressure. The crude was purified by chromatography on silica gel (elution with heptane/EtOAc: 90/10 to 50/50) to afford (R)-2-[(3-chloro-benzyl)-(3-methoxycarbonyl-propyl)-carbamoyl]-2-methyl-azetidine-1-carboxylic acid tert-butyl ester (27 g, yield=quantitative).

1. temperaturecooled to −5° C
2. stirringThe reaction was stirred at 20° C. for 2.5 h
3. extractionThe crude was extracted three times with DCM
4. washwashed with brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe crude was purified by chromatography on silica gel (elution with heptane/EtOAc: 90/10 to 50/50)