Reaction Steps
Palladium on carbon (10%, 46 mg) was added to 25e (230 mg, 0.38 mmol) in anhydrous THF (2.50 mL) and the solution was placed under an atmosphere of H2. After 12 hours, the solution was filtered through SiO2 (1:1 CH2Cl2:Acetone) and the eluent was concentrated to afford a yellow solid, which was used without further purification (177 mg, 99%). EDCI (61.5 mg, 0.32 mmol) and 1H-indole-2-carboxylic acid (41.4 mg, 0.26 mmol) were added to the amine (60.0 mg, 0.13 mmol) in 30% pyridine/CH2Cl2 (3.50 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 3:1 Hexane:Ether→40:1 CH2Cl2:Acetone) to afford a yellow solid, which was used without further purification (66.2 mg, 85%). Triethylamine (150 μL) was added to the carbonate (66.2 mg, 0.11 mmol) in MeOH (2.50 mL) and CH2Cl2 (2.50 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 40:1 CH2Cl2:Acetone) to afford 26m as a colorless amorphous solid (6.50 mg, 10%, 8.4% over 3 steps): 1H NMR (CD2Cl2, 500 MHz) 8.68 (s, 1H), 8.62 (s, 1H), 7.63-7.61 (m, 1H), 7.47 (dd, J=5.7, 3.3 Hz, 1H), 7.16-7.10 (m, 4H), 7.10-7.04 (m, 4H), 6.99 (t, J=8.2 Hz, 1H), 6.74 (d, J=8.0 Hz, 1H), 6.43 (dd, J=8.1, 0.7 Hz, 1H), 5.31 (d, J=2.9 Hz, 1H), 4.17 (t, J=6.8 Hz, 1H), 4.01 (dd, J=8.5, 2.9 Hz, 1H), 3.90 (d, J=13.1 Hz, 2H), 3.45 (s, 3H), 3.16 (d, J=8.6 Hz, 1H), 2.43 (s, 1H), 2.21 (s, 1H), 1.25 (s, 3H), 0.95 (s, 3H); 13C NMR (CDCl3, 125 MHz) 166.8, 155.4, 153.8, 140.2, 131.6, 130.2, 128.0, 127.6, 127.5 (2C), 127.4 (2C), 126.9, 125.1 (2C), 115.2, 108.3 (2C), 105.8 (2C), 97.1 (2C), 83.3 (2C), 77.2, 70.2, 67.9 (2C), 65.0, 60.6, 21.9, 13.1, 13.0; IR (film) νmax 3333, 2961, 2926, 2854, 1717, 1601, 1466, 1261, 1090, 1076, 1041, 800, 750 cm−1; HRMS (ESI+) m/z: [M+Na]+ calcd for C33H32N2O8, 607.2056; found, 607.2056.
