Reaction Steps
General procedure III for the Preparation of benzamide 29a-g: Palladium on carbon (10%, 10 mg) was added to a solution of 28a (85 mg, 0.2 mmol) in THF. The suspension was stirred overnight under a hydrogen atmosphere before it was filtered. The filtrate was concentrated and dried under vacuum for 4 hours before it was redissolved in THF (5 mL). To it was added freshly prepared acid chloride 9 (80 mg, 0.3 mmol) in THF (5 mL) and dry pyridine (32 mg, 0.4 mmol). The resulting mixture was stirred at room temperature overnight and concentrated to dryness. The residue was purified by column chromatography on silica using methylene chloride and methanol (10:1) as eluent to afford 29a as white amorphous solid (76 mg, 73%). 1H NMR (500 MHz, CDCl3), δ 8.79 (s, 1H), 8.71 (s, 1H), 7.81 (d, J=2.1, 1H), 7.77 (dd, J=8.3, 2.1, 1H), 7.34 (d, J=8.6, 1H), 7.18 (d, J=8.3, 1H), 6.89 (d, J=8.6, 1H), 5.25 (m, 1H), 4.52 (m, 1H), 3.33 (d, J=7.2, 2H), 2.76˜2.70 (m, 2H), 2.55˜2.45 (m, 2H), 2.40 (s, 3H), 2.35 (s, 6H), 2.15˜2.09 (m, 2H), 1.97˜1.92 (m, 2H), 1.78 (s, 3H), 1.74 (s, 3H). 13C NMR δ (125 MHz, CDCl3) 169.1, 165.6, 159.6, 157.1, 152.3, 149.7, 134.8, 134.5, 131.8, 129.5, 126.1, 125.8, 124.8, 123.1, 121.7, 120.8, 115.4, 113.5, 110.6, 77.4, 52.3, 46.2, 30.5, 29.0, 25.9, 21.1, 18.1, 8.6. IR (film) νmax 3400, 2922, 2851, 1765, 1711, 1672, 1607, 1526, 1493, 1369, 1248, 1202, 1175, 1099, 1040 cm−1. HRMS (ESI+) m/z Calc for [M+H+] C30H35N2O6 519.2495. found: 519.2485.
