1 H NMR ( 500 MHz , DMSO - d 6 ) : δ ppm 12 . 95 ( s , 1 H ) , 11 . 94 ( s , 1 H ) , 10 . 04 ( s , 1 H ) , 8 . 18 ( s , 1 H ) , 8 . 05 - 8 . 03 ( m , 1 H ) , 7 . 88 - 7 . 86 ( m , 1 H ) , 7 . 77 - 7 . 76 ( m , 1 H ) , 7 . 66 - 7 . 60 ( m , 2 H ) , 7 . 52 - 7 . 48 ( m , 1 H ) , 6 . 52 ( s , 1 H ) , 4 . 22 ( s , 3 H ) . ( ESI ) : m / z 363 . 1 [ M + H ] +.