反应详情

To a solution of (R)-ethyl 4-(3′-chlorobiphenyl-4-yl)-3-(2-methoxyoxazole-5-carboxamido)butanoate, intermediate 14, (103 mg, 0.23 mmol) in dioxane (3 mL) is added 4 N solution of HCl in dioxane (0.29 mL, 1.16 mmol). The crude was stirred at room temperature for 2 hrs. The crude is concentrated and is diluted in water and EtOAc. The organic layer is washed with brine, dried over MgSO4, filtered, and concentrated. 50% of the crude is purified via RP-HPLC (SunFire C18, H2O (0.1% TFA)/CH3CN) to give (R)-ethyl 4-(3′-chlorobiphenyl-4-yl)-3-(2-oxo-2,3-dihydrooxazole-5-carboxamido)butanoate (38 mg) as a white solid. HPLC retention time=1.66 minutes (condition A); MS (m+1)=429.4; 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.29 (t, J=7.1 Hz, 3H) 2.51-2.69 (m, 2H) 2.95 (dd, 1H) 3.05 (dd, 1H) 4.19 (q, 2H) 4.58-4.75 (m, 1H) 6.83 (d, J=8.8 Hz, 1H) 7.26-7.33 (m, 4H) 7.35 (t, J=7.7 Hz, 1H) 7.45 (dt, J=7.6, 1.5 Hz, 1H) 7.51 (d, J=8.3 Hz, 2H) 7.56 (t, J=1.8 Hz, 1H) 8.45 (br. s., 1H).

1. concentrationThe crude is concentrated
2. additionis diluted in water
3. washThe organic layer is washed with brine
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated
7. custom50% of the crude is purified via RP-HPLC (SunFire C18, H2O (0.1% TFA)/CH3CN)