1 H NMR ( CDCl 3 ) δ 8 . 58 ( 1 H , dd , J = 4 . 6 , 2 . 0 Hz ) , 7 . 62 ( 1 H , br d , J = 5 . 3 Hz ) , 7 . 44 ( 1 H , d , J = 2 . 0 Hz ) , 7 . 40 ( 1 H , ddd , J = 7 . 9 , 2 . 0 , 1 . 3 Hz ) , 7 . 34 ( 1 H , d , J = 2 . 0 Hz ) , 7 . 16 ( 1 H , dd , J = 7 . 9 , 4 . 6 Hz ) , 6 . 33 ( 1 H , s ) , 5 . 30 ( 1 H , s ) , 4 . 81 - 4 . 65 ( 4 H , m ) , 3 . 96 ( 1 H , br ) , 2 . 80 ( 2 H , m ) , 2 . 86 - 2 . 14 ( 2 H , m ) .