Reaction Steps
To a suspension of 432 (0.135 mmol) in THF (5 mL) were added TEA (0.094 mL, 0.675 mmol) and ethyl isocyanate (0.032 mL, 0.405 mmol) and stirred at RT for 1 h. The mixture was then concentrated, water was added to form a precipitate that was collected by filtration, rinsed with water, air-dried to afford the title compound 433 (78 mg, 88% yield for 2 steps) as a beige solid. 1H NMR (400 MHz, DMSO-d6) δ (ppm): 8.71 (s, 1H), 8.55 (d, J=1.6 Hz, 1H), 8.52 (d, J=5.6 Hz, 1H), 8.34 (s, 1H), 8.25 (d, J=8.4 Hz, 1H), 7.88 (dd, J=8.0, 2.0 Hz, 1H), 7.73 (dd, J=13.6, 2.4 Hz, 1H), 7.38 (t, J=9.0 Hz, 1H), 6.65 (dd, J=5.6, 0.8 Hz, 1H), 6.57 (bd, J=2.8 Hz, 1H), 6.27 (t, J=5.6 Hz, 1H), 4.06 (q, J=7.2 Hz, 2H), 3.84-3.75 (m, 5H), 3.69-3.61 (m, 2H), 3.02-2.94 (m, 2H), 2.59-2.51 (m, 1H), 1.18 (t, J=7.2 Hz, 3H), 0.97 (t, J=7.2 Hz, 3H), 0.68-0.62 (m, 2H), 0.45-0.40 (m, 2H). MS (m/z): 662.60 (M+H).
