“…1 H NMR (400 MHz, DMSO- d 6 ): δ 12.24 (1H, s, NH), 10.82 (1H, s, NH), 10.5 (1H, s, NH), 8.42 (1H, d, J = 7.6 Hz, 10–H), 7.66 (1H, dt, J = 7.8 and 1.2 Hz), 7.43 (1H, t, J = 7.2 Hz), 7.38 (1H, dd, J = 8.4 and 0.8 Hz), 7.15 (1H, dt, J = 7.6 and 1.2 Hz), 6.93–6.84 (3H, m), 1.64 (3H, s, CH 3 ). 13 C NMR (100 MHz, DMSO- d 6 ): δ 8.6 (CH 3 ), 48.9 (C spiro ), 94.8, 100.1, 108.8, 113.6, 116.7, 121.7, 123.2, 123.3, 124.0, 127.6, 132.2, 134.6, 136.5, 141.6, 145.6, 146.1, 152.0, 159.5 (CO), 179.0 (CO). MS (EI, 70 eV): m / z = 370 (M + , 5), 368 (M–2, 11), 246 (6), 236 (10), 152 (7), 123 (13), 111 (14), 97 (40), 83 (55), 69 (76), 57 (96), 43 (100).…”