Reaction Steps
Palladium on carbon (10%, 85.0 mg) was added to 25b (425 mg, 0.7283 mmol) in anhydrous THF (4.90 mL) and the solution was placed under an atmosphere of H2. After 6.5 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 (325 mg, 99%). EDCI (116 mg, 0.60 mmol) and 3′,6-dimethoxybiphenyl-3-carboxylic acid (125 mg, 0.4821 mmol) were added to the amine (108 mg, 0.2410 mmol) in 30% pyridine/CH2Cl2 (6.70 mL). After 12 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 3:1 Hexane:Ether→20:1 CH2Cl2:Acetone) to afford a colorless solid, which was used without further purification (51.0 mg, 31%). Triethylamine (150 μL) was added to the carbonate (51.0 mg, 0.074 mmol) in MeOH (2.50 mL). After 48 hours, the solvent was concentrated and the residue purified via column chromatography (SiO2, 40:1 CH2Cl2:Acetone) to afford 26b as a colorless amorphous solid (22.8 mg, 47%, 14% over 3 steps): 1H NMR (CD2Cl2, 400 MHz) 8.79 (s, 1H), 8.78 (s, 1H), 7.96 (dd, J=8.6, 2.4 Hz, 1H), 7.91 (d, J=2.4 Hz, 1H), 7.39 (t, J=7.9 Hz, 1H), 7.16-7.11 (m, 2H), 6.97-6.94 (m, 2H), 5.97 (s, 1H), 5.14 (d, J=6.5 Hz, 1H), 4.31 (t, J=3.5 Hz, 1H), 4.12-4.06 (m, 2H), 4.03 (dd, J=6.8, 1.8 Hz, 1H), 3.93 (s, 3H), 3.88 (s, 3H), 3.65 (s, 1H), 3.53 (s, 3H), 3.17 (d, J=4.8 Hz, 1H), 2.80 (s, 1H), 2.48 (s, 3H), 1.95-1.90 (m, 2H), 1.37 (s, 3H), 1.35 (s, 3H), 1.11 (t, J=7.4 Hz, 3H); 13C NMR (CDCl3, 125 MHz) 165.0, 164.6, 158.8, 158.3, 147.7, 145.7, 142.3, 137.8, 137.5, 131.3, 129.0, 128.2, 127.2, 124.9, 122.3, 121.2, 121.0, 115.111, 114.2, 112.1, 110.0, 106.2, 101.1, 81.7, 70.0, 69.0, 68.0, 64.8, 59.1, 54.9, 54.3, 24.7, 24.0, 21.3, 9.5, 9.1; IR (film) νmax 3398, 3196, 2964, 2935, 2359, 2330, 1705, 1580, 1526, 1504, 1381, 1242, 1124, 1094, 939, 808, 760, 735 cm−1; HRMS (ESI+) m/z: [M+H]+ calcd for C36H41NO11, 664.2758. found, 664.2754.
