Reaction Steps
A solution mixture of 7 (0.17 g, 0.6 mmol), 3a (0.24 g, 0.8 mmol) and piperidine (0.1 mL) in ethanol (40 mL) was heated to reflux overnight. After cooling down to room temperature, the organic solvent was removed. The residue was purified by precipitation from methanol and ethyl acetate to afford SLOH-Pr (0.14 g) in 41% yield. 1H NMR (400 MHz, DMSO-d6) δ 9.29 (d, J=6.8 Hz, 1H), 9.15 (d, J=8.4 Hz, 1H), 8.88 (s, 1H), 8.51 (d, J=6.8 Hz, 1H), 8.45 (d, J=16 Hz, 1H), 8.37 (d, J=16 Hz, 1H), 8.28-8.24 (m, 2H), 8.13 (d, J=8.4 Hz, 1H), 8.05 (t, J=8.0 Hz, 1H), 7.77 (d, J=8.8 Hz, 1H), 7.70 (d, J=8.4 Hz, 1H), 7.52 (t, J=7.6 Hz, 1H), 7.31 (t, J=7.2 Hz, 1H), 5.01 (t, J=7.2 Hz, 2H), 4.86 (t, J=5.2 Hz, 1H), 4.63 (t, J=4.8 Hz, 2H), 3.84 (t, J=5.2 Hz, 2H), 3.55 (tr, J=5.2 Hz, 2H), 3.47 (t, J=5.6 Hz, 2H), 3.31 (t, J=4.8 Hz, 2H), 3.11 (s, 3H), 2.13 (t, J=6.0 Hz, 2H). 13C NMR (400 MHz, DMSO-d6) δ 153.3, 147.3, 145.1, 142.2, 140.9, 137.9, 135.0, 128.8, 127.4, 126.8, 126.7, 126.5, 126.4, 122.8, 122.2, 121.8, 120.4, 119.9, 119.0, 116.3, 115.2, 110.5, 110.4, 71.3, 69.8, 68.9, 58.1, 57.6, 54.2, 42.9, 32.0. HRMS (MALDI-TOF) m/z Calcd for C31H33N2O3 481.2485. Found 481.2458 [M]+.
