1 H NMR ( CDCl 3 ) δ 8 . 64 ( 1 H , br dd , J = 4 . 3 , 1 . 8 Hz ) , 8 . 47 ( 1 H , d , J = 2 . 4 Hz ) , 8 . 10 ( 1 H , br ) , 7 . 78 ( 1 H , d , J = 2 . 4 Hz ) , 7 . 74 ( 1 H , dd , J = 7 . 9 , 1 . 8 Hz ) , 7 . 26 ( 1 H , dd , J = 7 . 9 , 4 . 3 Hz ) , 4 . 83 ( 1 H , dd , J = 18 . 3 , 4 . 9 Hz ) , 4 . 71 ( 1 H , dd , J = 18 . 3 , 4 . 9 Hz ) , 3 . 89 ( 1 H , d , J = 6 . 1 Hz ) , 3 . 05 ( 1 H , d , J = 6 . 1 Hz ) , 2 . 83 ( 1 H , m ) , 2 . 62 ( 1 H , m ) , 2 . 40 ( 1 H , m ) , 2 . 16 ( 1 H , m ) .