Reaction Steps
General procedure IV for the preparation of compounds 31a-g: Compound 29a (52 mg, 0.1 mmol) was dissolved in 10% triethylamine/methanol (3 mL). The solution was stirred at room temperature overnight and concentrated. The residue was purified by column chromatography on silica by using methylene chloride and methanol (10:1) to give 31a as a white, amorphous solid (37 mg, 73%). 1H NMR (500 MHz, DMSOd6) δ 9.22 (s, 1H), 8.47 (s, 1H), 7.68˜7.66 (m, 2H), 7.53 (d, J=8.7, 1H), 7.11 (d, J=8.9, 1H), 6.90 (d, J=8.7, 1H), 5.30 (m, 1H), 4.57 (m, 1H), 3.27 (d, J=7.3, 2H), 2.62˜2.54 (m, 2H), 2.34˜2.28 (m, 2H), 2.22 (s, 3H), 2.21 (s, 3H), 1.96˜1.92 (m, 2H), 1.76˜1.72 (m, 2H), 1.71 (s, 3H), 1.69 (s, 3H). 13C NMR (125 MHz, DMSOd6) δ 165.3, 158.8, 158.4, 156.6, 149.5, 131.9, 129.2, 127.8, 127.7, 126.8, 126.0, 124.0, 122.3, 121.3, 114.6, 113.4, 112.7, 110.8, 72.1, 51.8, 45.7, 30.2, 27.9, 25.6, 17.7, 8.2. IR (film) νmax 3421, 1703, 1666, 1601, 1528, 1504, 1366, 1248, 1178, 1150, 1094, 1040 cm−1. HRMS (ESI+) m/z Calc for [M+H+] C28H33N2O5 477.2389. found: 477.2397.
