Reaction Steps
To a solution of 2-[4-(N-benzyloxycarbonylamino)-2-(5-methoxyindole-2-carboxamido)naphthalen-1-yl]ethanol (0.4 g, 0.78 mmol) and triethylamine (0.44 mL, 3.14 mmol) in THF (20 mL) was added methanesulfonyl chloride (0.24 mL, 3.14 mmol) with ice bath and stirred for 1 h. The reaction mixture was diluted with CH2Cl2 (50 mL) and washed with H2O (10 mL) and saturated aqueous NaCl (20 mL), and then the organic layer was dried (Na2SO4) and concentrated under reduced pressure. The residue was purified by silica-gel column (30% AcOEt-Petroleum ether) to yield as a yellow foam 2-[4-(N-benzyloxycarbonylamino)-2-(5-methoxyindole-2-carboxamido)naphthalen-1-yl]ethyl methanesulfonate (0.28 g, 61%): mp 160° C. (decomp.); 1H NMR (CDCl3, 500 MHz) δ 9.09 (brs, 1H), 8.36 (brs, 1H), 7.89 (d, 9.0, 1H), 7.87 (d, 9.0, 1H), 7.57 (t, 8.5, 1H), 7.48 (d, 7.5, 2H), 7.40 (t, 7.5, 2H), 7.34 (m, 2H), 7.17 (s, 1H), 7.13 (s, 1H), 7.00 (d, 8.5, 1H), 7.00 (d, 9.0, 1H), 4.70 (brs, 2H), 4.61 (t, 6.0, 2H), 4.50 (s, 2H), 3.88 (s, 3H), 3.54 (t, 6.0, 2H), 2.84 (s, 3H); ); FABMS (NBA) m/z 543 (M−CO2+), IR (neat) νmax 3400, 1643, 1591, 1530, 1479, 1453, 1351, 1231, 1213, 1173, 1142, 1076, 1031, 974, 947, 841, 805, 761, 734, 699 cm−1.
