1H NMR (400 MHz, CDCl3) δ 8.95 (s, 1H), 8.21 (d, J = 5.8 Hz, 1H), 7.39 – 7.33 (m, 3H), 7.26 – 7.20 (m, 3H), 6.98 (d, J= 5.8 Hz, 1H), 6.70 (d, J = 2.8 Hz, 1H), 5.64 (s, 1H), 5.38 (s, 1H). 1H NMR (400 MHz, CDCl3) δ 8.95 (s, 1H), 8.22 (d, J= 5.8 Hz, 1H), 7.43 – 7.33 (m, 3H), 7.28 – 7.25 (m, 2H), 7.21 (d, J = 3.2 Hz, 1H), 6.99 (d, J = 5.8 Hz, 1H), 6.71 (dd, J = 3.3, 0.7 Hz, 1H), 5.65 (s, 1H), 5.39 (s, 1H). HRMS (EI): calcd for C15H12N2: 220.1000, found: 220.0997。