1 H - NMR : ( 300 MHz , DMSO - d 6 ) δ 11 . 48 ( s , 1 H ) , 9 . 88 ( s , 1 H ) , 8 . 22 ( s , 1 H ) , 7 . 41 ( dd , 1 H , J = 2 . 25 Hz ) , 7 . 29 ( m , 2 H , J = 7 . 53 Hz ) , 6 . 05 ( s , 1 H ) , 4 . 47 ( s , 1 H ) , 3 . 53 ( d , 7 H , J = 6 . 6 Hz ) , 2 . 41 ( s , 5 H ) , 2 . 24 ( s , 3 H ) , 1 . 24 ( broad singlet , 2 H ) ;