1 H NMR ( CDCl 3 ) δ 8 . 87 ( 1 H , d , J = 4 . 6 Hz ) , 7 . 73 ( 1 H , d , J = 7 . 9 Hz ) , 7 . 52 ( 1 H , dd , J = 7 . 9 , 4 . 6 Hz ) , 7 . 33 ( 1 H , d , J = 1 . 3 Hz ) , 7 . 16 ( 1 H , d , J = 1 . 3 Hz ) , 7 . 05 ( 1 H , br d , J = 5 . 9 Hz ) , 4 . 71 ( 1 H , dd , J = 14 . 5 , 5 . 9 Hz ) , 4 . 64 ( 1 H , dd , J = 14 . 5 , 5 . 9 Hz ) , 3 . 17 ( 1 H , m ) , 3 . 00 ( 1 H , m ) , 2 . 79 ( 1 H , m ) , 2 . 52 ( 1 H , m ) , 2 . 46 ( 3 H , s ) .