1 H NMR ( CDCl 3 ) δ 8 . 54 ( 1 H , dd , J = 4 . 6 , 2 . 0 Hz ) , 7 . 40 ( 1 H , d , J = 9 . 2 Hz ) , 7 . 21 ( 1 H , d , J = 2 . 0 Hz ) , 7 . 15 ( 1 H , dd , J = 9 . 2 , 4 . 6 Hz ) , 7 . 09 ( 1 H , d , J = 2 . 0 Hz ) , 6 . 31 ( 1 H , s ) , 5 . 66 ( 1 H , br ) , 5 . 19 ( 1 H , s ) , 4 . 56 ( 1 H , dd , J = 14 . 5 , 5 . 9 Hz ) , 4 . 44 ( 1 H , dd , J = 14 . 5 , 5 . 9 Hz ) , 3 . 71 ( 1 H , br t , J = 5 . 3 Hz ) , 2 . 63 ( 2 H , m ) , 2 . 45 ( 3 H , s ) , 2 . 35 ( 1 H , m ) , 2 . 04 ( 1 H , m ) .