The preparation of N-SUCCINIMIDYL 7-METHOXYCOUMARIN-3-CARBOXYLATE is as follows:
Method 1: Under magnetic stirring, 1 mmol of dimethylformamide (5 ml) and N-hydroxysuccinimide (115 mg, 1 mmol) were added to a solution of 7-methoxycoumarin-3-carboxylic acid. The mixture was cooled to -10 °C and held for 1 hour, and then N,N'-dicyclohexylcarbodiimide (226.96 mg, 1.1 mmol) was added. The mixture was stirred at -10 °C for 1 hour, and then stirred at room temperature for 3 hours. The mixture was then filtered to remove dicyclohexylurea (DCU), and then a mixture of isopropanol/hexane (1/10) was added to precipitate the product. After filtration and vacuum drying, N-SUCCINIMIDYL 7-METHOXYCOUMARIN-3-CARBOXYLATE was obtained. 1H NMR (DMSO-d6)δppm: 8.76 (2H, s); 7.57 (1H, d, J=8.5Hz); 6.95 (1H, d, J=8.5Hz); 6.85 (1H, s); 3.95 (3H, s); 3.34 (2H, s), 2.90 (4H, s).
