Reaction Steps
To a stirred solution of trans 3-amino-2-carbo-t-butoxymethoxy-1,2,3,4-tetrahydronaphthalene (550 mg, 1.98 mmol) and 5-chloroindole-2-carboxylic acid (466 mg, 2.39 mmol) in tetrahydrofuran (12 mL) at room temperature under nitrogen was added 1-[3-dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (760 mg, 2.39 mmol), 1-hydroxy-7-azabenzotriazole (540, 2.39 mmol), and diisopropylethylamine (0.4 mL). After 1 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 and dried over anhydrous magnesium sulfate. The solvent was evaporated and the resulting residue was purified by silica gel chromatography (20% ethyl acetate in hexane was used) to obtain the title compound (653 mg, 72%). 13C NMR (400 MHz, CDCl3) δ 172.31, 162.11, 134.72, 133.82, 132.8, 132.7, 128.8, 128.7, 126.6, 126.3, 125.7, 124.3, 121.0, 113.2, 102.6, 83.3, 77.6, 66.1, 51.7, 35.8, 34.4, 28.2. 1H NMR (400 MHz, CDCl3) δ 9.22 (s, 1H), 8.92 (d, J=4.0 Hz, 1H), 7.60 (s, 1H), 7.35 (d, J=8.0 Hz, 1H), 7.22 (dd, J=2.2, 7.8 Hz, 1H), 7.07-7.19 (m, 3H), 4.27 (d, J=17.6 Hz, 1H), 4.20 (m, 1H), 4.12 (d, J=17.6 Hz, 1H), 3.91 (dd, J=4.5, 16.8 Hz, 1H), 3.76 (dt, J=5.3, 8.0 Hz, 1H), 3.24 (dd, J=5.2, 16.8 Hz, 1H), 2.92 (dd, J=9.5, 15.0 Hz, 1H), 2.77 (dd, J=9.5, 15.0 Hz, 1H). MS [M+H]+, 455; [M−H]−, 453.
