1 H NMR ( DMSO d 6 ) δ 9 . 32 ( 1 H , br d , J = 7 . 3 Hz ) , 8 . 85 ( 1 H , d , J = 4 . 3 Hz ) , 7 . 98 ( 1 H , br d , J = 7 . 9 Hz ) , 7 . 74 ( 1 H , dd , J = 7 . 9 , 4 . 3 Hz ) , 7 . 60 ( 1 H , dd , J = 8 . 6 , 6 . 1 Hz ) , 7 . 40 ( 1 H , br d , J = 9 . 2 Hz ) , 7 . 28 ( 1 H , dt , J = 8 . 6 , 2 . 4 Hz ) , 5 . 26 ( 1 H , m ) , 2 . 83 ( 1 H , m ) , 2 . 76 - 2 . 51 ( 3 H , m ) , 1 . 44 ( 3 H , d , J = 7 . 3 Hz ) .