反应详情

BOP-Cl (36.4 mg, 0.143 mmol) was added to a mixture of crude tert-butyl 3-hydroxy-3-(4-(N′-hydroxycarbamimidoyl)phenyl)azetidine-1-carboxylate (Intermediate 4, 40 mg, 0.13 mmol), 3-(1-(3,5-dichlorophenyl)cyclohexyl)propanoic acid (39.2 mg, 0.13 mmol) and diisopropylethyl amine (0.045 mL, 0.26 mmol) in DMF (3 mL). The mixture was stirred at room temperature for 2 h, and a 1M solution of tetra-n-butylammonium fluoride in THF (0.13 mL, 0.13 mmol) was added. The mixture was heated to 80° C. overnight, diluted with ethyl acetate, and washed with saturated aqueous NaCl solution. The organic layer was dried (MgSO4), filtered, and concentrated. The crude product was purified on a 24 g ISCO cartridge and eluted with EtOAc-hexanes gradient to obtain tert-butyl 3-(4-(5-(2-(1-(3,5-dichlorophenyl)cyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)phenyl)-3-hydroxyazetidine-1-carboxylate (56 mg, 50% yield, HPLC purity: 80%). HPLC retention time=4.71 minutes (Waters Sunfire C18 4.6×50 mm) eluting with 10-90% aqueous methanol with 0.1% TFA over a 4 minute gradient. LC/MS: m/e 572.25 (M+H)+.

1. temperatureThe mixture was heated to 80° C. overnight
2. washwashed with saturated aqueous NaCl solution
3. dry with materialThe organic layer was dried (MgSO4)
4. filtrationfiltered
5. concentrationconcentrated
6. customThe crude product was purified on a 24 g ISCO cartridge
7. washeluted with EtOAc-hexanes gradient