1 H NMR ( CDCl 3 , 300 MHz ) : δ ppm 9 . 72 ( s , 1 H ) , 8 . 95 ( s , 1 H ) , 8 . 21 ( d , J = 7 . 5 Hz , 1 H ) , 8 . 08 ( d , J = 8 . 7 Hz , 1 H ) , 7 . 91 ( s , 1 H ) , 7 . 83 ( d , J = 8 . 7 Hz , 1 H ) , 7 . 66 - 7 . 52 ( m , 3 H ) , 6 . 83 ( t , J = 54 . 6 Hz , 1 H ) , 4 . 37 ( s , 3 H ) . ( ESI ) : m / z 386 . 8 [ M + H ] +.