1 H NMR ( DMSO - d 6 , 400 MHz ) : δ ppm 11 . 92 ( s , 1 H ) , 10 . 04 ( s , 1 H ) , 8 . 18 ( s , 1 H ) , 8 . 05 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 87 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 52 ( d , J = 7 . 6 Hz , 1 H ) , 7 . 34 - 7 . 26 ( m , 2 H ) , 7 . 08 ( d , J = 6 . 8 Hz , 1 H ) , 6 . 70 ( s , 1 H ) , 4 . 22 ( s , 3 H ) , 2 . 26 - 2 . 19 ( m , 1 H ) , 0 . 94 - 0 . 92 ( m , 2 H ) , 0 . 72 - 0 . 71 ( m , 2 H ) . ( ESI ) : m / z 359 . 0 [ M + H ] +.