1 H NMR ( CDCl 3 ) δ 8 . 63 ( 1 H , dd , J = 4 . 6 , 2 . 0 Hz ) , 7 . 67 ( 2 H , m ) , 7 . 44 ( 2 H , m ) , 7 . 30 - 7 . 04 ( 2 H , m ) , 4 . 75 ( 2 H , d , J = 5 . 9 Hz ) , 3 . 86 ( 1 H , d , J = 5 . 9 Hz ) , 3 . 03 ( 1 H , d , J = 5 . 9 Hz ) , 2 . 99 - 2 . 00 ( 4 H , m ) .