1H NMR (DMSO-d6) δ 11.58 (s, 1H), 8.48 (apar t, J = 8 Hz, 2H), 7.61 (apar d, J = 8 Hz, 2H), 7.41 (d, J = 8 Hz, 1H), 7.23 (s, 1H), 7.17 (t, J = 8 Hz, 1H), 7.02 (t, J = 8 Hz, 1H), 4.55 (m, 1H), 4.37 (m, 1H), 4.25 (d, J = 20 Hz, 1H), 4.10 (d, J = 20 Hz, 1H), 3.23 (s, 3H), 3.06 (m, 2H), 2.27 (m, 1H), 2.07 (m, 1H), 1.91 (m, 1H), 1.79 (m, 1H), 1.69 (m, 3H), 0.94 (s, 9H); MS (ESI+) for C25H34N4O5m/z 471.2 (M + H)+; anal. calcd for C25H34N4O5·0.2 ethyl acetate·0.75 H2O: C, 61.76; H, 7.46; N, 11.17.