Reaction Steps
Routine allyl ester cleavage conditions were previously described by Friedrich-Bochnitschek, S.; Waldmann, H.; Kunz, H. J. Org. Chem. 1989, 54, 751-756. To a solution of 3(R)-[3-[(4-cyanophenyl)acetyl]-1H-pyrrol-1-yl]-N-[2,2-dimethyl-1(S)-(methylcarbamoyl)propyl]succinamic acid allyl ester (247 mg, 0.501 mmol) in acetonitrile (2 mL) was added in succession Pd(PPh3)4 (29 mg, 0.026 mmol) and morpholine (226 μL, 2.60 mmol). The resultant mixture was carefully purged with argon. After 30 min, the resultant green mixture was stirred with 10% aqueous KHSO4 (20 mL) and extracted with CHCl3 (35 mL). The organic layer was washed with 10% aqueous KHSO4 (20 mL), dried over Na2SO4, and concentrated. Flash column chromatography with 1% HOAc/3% MeOH/CHCl3 and drying via azeotrope with n-heptane gave 243 mg (94%) of 3(R)-[3-[(4-cyanophenyl)acetyl]-1H-pyrrol-1-yl]-N-[2,2-dimethyl-1(S)-(methylcarbamoyl)propyl]succinamic acid as a yellow solid. 1H NMR (CD3OD): δ 8.09 (d, 1H, J=8.7 Hz), 8.05 (dd, 1H, J=2.8, 6.9 Hz), 7.78 (dd, 1H, J=1.9, 1.9 Hz), 7.66 (d, 2H, J=8.4 Hz), 7.46 (d, 2H, J=8.4 Hz), 6.90 (dd, 1H, J=2.2, 2.2 Hz), 6.59 (dd, J=1.9, 3.1 Hz), 5.33 (t, 1H, J=7.5 Hz), 4.22-4.15 (m, 3H), 3.24 (t, 1H, J=8.7 Hz), 2.98 (dd, 1H, J=5.3, 17.4 Hz), 2.66 (d, 3H, J=4.7 Hz), 0.99 (s, 9H). IR (KBr): 3332, 2696, 2230, 1719, 1654, 1532, 1412, 1177 cm-1. HRFABMS: Calculated for C24H29N4O5 (M+H+): 453.2125. Found: 453.2125. Anal. Calculated for C24H28N4O5.0.5 HOAc.0.3 CHCl3 : C, 58.62; H, 5.89; N, 10.81. Found: C, 58.41; H, 5.72; N, 10.50.
