1 H NMR ( CDCl 3 ) δ 8 . 49 ( 1 H , dd , J = 4 . 3 , 1 . 2 Hz ) , 8 . 07 ( 1 H , br t , J = 5 . 5 Hz ) , 7 . 69 ( 1 H , d , J = 7 . 9 Hz ) , 7 . 39 ( 1 H , dd , J = 7 . 9 , 4 . 3 Hz ) , 6 . 62 ( 2 H , m ) , 4 . 46 ( 2 H , m ) , 4 . 01 ( 1 H , br t , J = 5 . 5 Hz ) , 2 . 99 ( 1 H , m ) , 2 . 64 ( 1 H , m ) , 2 . 42 - 2 . 28 ( 2 H , m ) .