1 H NMR ( DMSO d 6 ) δ 8 . 44 ( 1 H , br ) , 8 . 43 ( 1 H , d , J = 4 . 6 Hz ) , 7 . 56 ( 1 H , d , J = 7 . 3 Hz ) , 7 . 49 ( 1 H , d , J = 2 . 0 Hz ) , 7 . 35 ( 1 H , d , J = 2 . 0 Hz ) , 7 . 22 ( 1 H , dd , J = 7 . 3 , 4 . 6 Hz ) , 5 . 41 ( 1 H , d , J = 5 . 3 Hz ) , 5 . 09 ( 1 H , dd , J = 11 . 9 , 5 . 3 Hz ) , 4 . 38 ( 2 H , d , J = 4 . 6 Hz ) , 4 . 08 ( 1 H , dd , J = 7 . 9 , 5 . 3 Hz ) , 2 . 47 ( 1 H , m ) , 2 . 36 ( 3 H , s ) , 1 . 97 ( 1 H , m ) .