1 H NMR ( CDCl 3 ) δ 8 . 69 ( 1 H , br s ) , 7 . 46 ( 1 H , d , J = 1 . 2 Hz ) , 7 . 42 ( 1 H , dd , J = 8 . 6 , 6 . 1 Hz ) , 7 . 20 ( 1 H , dd , J = 7 . 9 , 2 . 4 Hz ) , 7 . 20 ( 1 H , br ) , 7 . 01 ( 1 H , dt , J = 8 . 6 , 2 . 4 Hz ) , 4 . 64 ( 1 H , dd , J = 14 . 7 , 6 . 1 Hz ) , 4 . 61 ( 1 H , dd , J = 14 . 7 , 6 . 1 Hz ) , 3 . 10 ( 1 H , m ) , 2 . 97 ( 1 H , m ) , 2 . 79 ( 1 H , m ) , 2 . 54 ( 1 H , m ) , 2 . 40 ( 3 H , s ) .