1 H NMR ( MeOD , 400 MHz ) : δ ppm 8 . 63 ( s , 1 H ) , 8 . 36 ( s , 1 H ) , 8 . 10 ( s , 1 H ) , 7 . 83 ( d , J = 7 . 6 Hz , 1 H ) 7 . 70 - 7 . 58 ( m , 3 H ) , 6 . 92 ( t , J = 54 . 8 Hz , 1 H ) , 6 . 72 ( s , 1 H ) , 2 . 71 ( s , 3 H ) . ( ESI ) : m / z 369 . 0 [ M + H ] +.