1 H NMR ( DMSO - d 6 , 400 MHz ) : δ ppm 12 . 06 ( s , 1 H ) , 9 . 78 ( s , 1 H ) , 8 . 09 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 99 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 81 ( d , J = 7 . 6 Hz , 1 H ) , 7 . 73 - 7 . 67 ( m , 2 H ) , 7 . 61 - 7 . 58 ( m , 1 H ) , 7 . 52 ( s , 1 H ) , 7 . 15 ( t , J = 54 . 4 Hz , 1 H ) , 7 . 13 ( s , 1 H ) , 6 . 57 ( m , 1 H ) , 4 . 05 ( s , 3 H ) . ( ESI ) : m / z 368 . 0 [ M + H ] +.