Reaction Steps
To a stirred solution of trans 2-amino-3-carboethoxy-1,2,3,4-tetrahydronaphthalene trifluoroacetic acid salt (130 mg, 0.39 mmol) and 5-chloroindole-2-carboxylic acid (92 mg, 0.47 mmol) in tetrahydrofuran (8 mL) at room temperature under nitrogen was added 1-[3-dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (153 mg, 0.78 mmol), 1-hydroxy-7-azabenzotriazole (106, 0.78 mmol), and diisopropylethylamine (0.14 mL, 0.78 mmol). After 2 h, the reaction mixture was diluted with ethyl acetate. The organic layer was washed with 1.0 M aqueous hydrochloric acid solution, 1.0 M aqueous sodium hydroxide solution and brine, dried over anhydrous magnesium sulfate, and concentrated under vacuum. The resulting residue was suspended in methanol. The suspension was filtered and the solid was washed with methanol to obtain the title compound (120 mg, 77%). 13C NMR (400 MHz, d8-tetrahydrofuran) δ 173.5, 161.3, 136.1, 135.2, 135.0, 134.6, 129.8, 129.5, 129.1, 126.9, 126.8, 126.0, 124.4, 121.5, 114.0, 101.8, 61.1, 48.5, 46.5, 36.0, 32.5, 14.5. 1H NMR (400 MHz, d8-tetrahydrofuran) δ 11.18 (s, 1H), 7.82 (d, J=8.4 Hz, 1H), 7.56 (s, 1H), 7.38 (d, J=7.8 Hz, 1H), 7.04-7.17 (m, 4H), 6.89 (s, 1H), 4.62 (m, 1H), 4.05 (q, J=7.0 Hz, 2H), 3.15-3.26 (m, 2H), 2.87-3.09 (m, 3H), 1.11 (t, J=7.0 Hz, 3H). MS [M+H]+, 397; [M−H]−, 395.
