Reaction Steps
Palladium on carbon (10%, 4 mg) was added to 25c (19.0 mg, 0.033 mmol) in anhydrous THF (220 μL) 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 (14.5 mg, 99%). EDCI (15.6 mg, 0.081 mmol) and 1H-indole-2-carboxylic acid (10.5 mg, 0.065 mmol) was added to the amine (14.5 mg, 0.033 mmol) in 30% pyridine/CH2Cl2 (1.00 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 40:1 CH2Cl2:Acetone) to afford a colorless solid, which was used without further purification (10.0 mg, 50%). Triethylamine (150 μL) was added to the carbonate (10.0 mg, 0.017 mmol) in MeOH (2.5 mL) and CH2Cl2 (2.50 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 10:1 CH2Cl2:Acetone) to afford 26k as a colorless amorphous solid (6.00 mg, 46%, 23% over 3 steps): 1H NMR (CDCl3, 500 MHz) δ 8.16 (s, 1H), 7.52 (s, 1H), 7.34-7.30 (m, 5H), 6.75 (s, 1H), 4.93 (d, J=5.0 Hz, 1H), 4.56-4.51 (m, 1H), 4.23 (t, J=4.0 Hz, 1H), 3.98-3.96 (m, 1H), 3.76 (s, 1H), 3.43 (s, 3H), 3.06 (d, J=4.3 Hz, 1H), 2.65 (s, 1H), 2.38 (s, 3H), 1.33 (dd, J=11.2, 6.1 Hz, 6H), 1.29 (s, 3H), 1.27 (s, 3H); 13C NMR (CDCl3, 125 MHz) δ 157.6, 152.1, 146.6, 146.0, 142.1, 134.5, 127.7, 127.5, 127.2, 122.2, 121.3 (2C), 120.2 (2C), 115.0 (2C), 108.1 (2C), 101.2, 81.6, 71.2, 68.9, 68.1, 66.5, 59.0, 24.8, 23.6, 20.8 (2C), 9.1; IR (film) νmax cm−1 3406, 2930, 2375, 1705, 1522, 1394, 1229, 1205, 1111, 1078, 1049, 933, 793, 739, 698; HRMS (ESI+) m/z: [M+Na]+ calcd for C30H34N2O9, 589.2162. found, 589.2111.
