Reaction Steps
A mixture of 2-[(3-methyl-2′-oxospiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-1′(2′H)-yl)methyl]-1,3-oxazole-4-carboxylic acid (0.32 g, 0.76 mmol), dimethylamine hydrochloride (0.13 g, 1.52 mmol), 1-hydroxybenzotriazole hydrate (0.16 g, 1.17 mmol), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (0.21 g, 1.07 mmol), 4-methylmorpholine (0.23 mL, 2.07 mmol) and anhydrous N,N-dimethylformamide (10 mL) was stirred at ambient temperature for 16 h. The reaction mixture was concentrated in vacuo, and the residue recrystallized from diethyl ether to afford N,N-dimethyl-2-[(3-methyl-2′-oxospiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-1′(2′H)-yl)methyl]-1,3-oxazole-4-carboxamide (0.23 g, 68%) as a colorless solid: mp 87-89° C. (diethyl ether); 1H NMR (300 MHz, CDCl3) δ 8.10 (s, 1H), 7.48-7.5 (m, 1H), 7.31-7.25 (m, 1H), 7.14-7.11 (m, 1H), 7.05-6.95 (m, 3H), 5.28-5.06 (m, 3H), 4.87-4.84 (m, 1H), 3.32 (s, 3H), 3.06 (s, 3H), 2.43 (s, 3H); 13C NMR (75 MHz, CDCl3) δ 175.8, 164.0, 161.7, 158.2, 157.1, 154.9, 143.7, 141.3, 137.2, 130.1, 129.5, 124.0, 123.9, 123.2, 118.0, 109.3, 108.6, 107.9, 81.3, 56.3, 38.4, 37.5, 36.2, 9.8; MS (ES+) m/z 444.8 (M+1).
