1 H NMR ( CDCl 3 ) δ 8 . 59 ( 1 H , br dd , J = 4 . 3 , 1 . 8 Hz ) , 7 . 45 ( 1 H , br dd , J = 7 . 9 , 1 . 8 Hz ) , 7 . 41 ( 1 H , dd , J = 8 . 6 , 6 . 1 Hz ) , 7 . 18 ( 1 H , dd , J = 7 . 9 , 4 . 3 Hz ) , 7 . 16 ( 1 H , dd , J = 6 . 1 , 3 . 1 Hz ) , 7 . 14 ( 1 H , br ) , 7 . 03 ( 1 H , ddd , J = 8 . 5 , 7 . 9 , 3 . 1 Hz ) , 5 . 46 ( 1 H , m ) , 3 . 85 ( 1 H , d , J = 6 . 1 Hz ) , 3 . 02 ( 1 H , d , J = 6 . 1 Hz ) , 2 . 77 ( 1 H , m ) , 2 . 57 ( 1 H , m ) , 2 . 34 ( 1 H , m ) , 2 . 15 ( 1 H , m ) , 1 . 60 ( 3 H , d , J = 6 . 7 Hz ) .