反应详情

A mixture of 3-amino-3-(3-cyclopentyloxy-4-methoxyphenyl)propanoic acid (3.00 g, 10.8 mmol) and sodium carbonate (1.20 g, 11.3 mmol) in acetonitrile (30 mL) and water (30 mL) under nitrogen was stirred at room temperature for 15 minutes. To the resulting solution was added N-ethoxycarbonyl phthalimide (2.36 g, 10.8 mmol). The resulting mixture was stirred at room temperature for 18 hours. Most of solvent was removed in vacuo. To the solution was added hydrochloric acid (6N) until the pH of solution <1 to give a suspension and stirring was continued for 1 hour. The suspension was filtered, the solid was washed with water (2×10 mL), and then was dried in a vacuum oven overnight (60° C., <1 torr) to afford 3-(3-cyclopentyloxy-4-methoxyphenyl)-3-phthalimidopropanoic acid as a white solid (3.0 g, 68% yield): mp, 168.0-169.0° C.; 1H NMR (DMSO-d6) δ1.55-1.88 (m, 8H, C5H8), 3.27 (dd, J=6.9, 16.5 Hz, 1H, CHH), 3.51 (dd, J=8.9, 16.5 Hz, 1H, CHH), 3.71 (s, 3H, CH3), 4.71-4.75 (m, 1H, CH), 5.61 (dd, J=6.9, 8.8 Hz, 1H, NCH), 6.87-6.95 (m, 2H, Ar), 7.03 (br s, 1H, Ar), 7.81-7.91 (m, 4H, Ar), 12.4 (br s, 1H, OH); 13C NMR (DMSO-d6) δ23.51, 32.14, 32.17, 36.07, 50.08, 55.52, 79.57, 112.15, 113.97, 119.39, 123.17, 131.09, 131.19, 134.66, 146.77, 149.16, 167.67, 171.72; Anal Calcd for C23H23NO6: C, 67.47; H, 5.66; N, 3.42. Found: C, 67.21; H, 5.46; N, 3.45.

1. stirringThe resulting mixture was stirred at room temperature for 18 hours
2. customMost of solvent was removed in vacuo
3. additionTo the solution was added hydrochloric acid (6N) until the pH of solution <1
4. customto give a suspension
5. stirringstirring
6. waitwas continued for 1 hour
7. filtrationThe suspension was filtered
8. washthe solid was washed with water (2×10 mL)
9. customwas dried in a vacuum oven overnight (60° C., <1 torr)