1 H NMR ( CDCl 3 ) δ 8 . 54 ( 1 H , dd , J = 4 . 9 , 1 . 2 Hz ) , 7 . 42 ( 1 H , dd , J = 7 . 9 , 1 . 2 Hz ) , 7 . 29 - 7 . 22 ( 1 H , m ) , 7 . 16 ( 1 H , dd , J = 7 . 9 , 4 . 9 Hz ) , 6 . 85 - 6 . 74 ( 2 H , m ) , 6 . 32 ( 1 H , d , J = 1 . 8 Hz ) , 5 . 66 ( 1 H , br ) , 5 . 20 ( 1 H , d , J = 1 . 8 Hz ) , 4 . 42 ( 2 H , br d , J = 5 . 5 Hz ) , 3 . 75 ( 1 H , br t , J = 5 . 5 Hz ) , 2 . 66 - 2 . 63 ( 2 H , m ) , 2 . 33 ( 1 H , m ) , 2 . 06 ( 1 H , m ) .