1 H NMR ( CDCl 3 ) δ 8 . 87 ( 1 H , ddd , J = 4 . 3 , 1 . 8 , 1 . 2 Hz ) , 7 . 67 ( 1 H , dd , J = 7 . 9 , 2 . 4 Hz ) , 7 . 48 ( 1 H , dd , J = 7 . 9 , 4 . 3 Hz ) , 7 . 43 ( 1 H , d , J = 1 . 8 Hz ) , 7 . 33 ( 1 H , d , J = 8 . 6 Hz ) , 7 . 29 ( 1 H , dd , J = 8 . 6 , 2 . 4 Hz ) , 7 . 12 ( 1 H , br ) , 5 . 42 ( 1 H , m ) , 3 . 18 ( 1 H , m ) , 3 . 02 ( 1 H , m ) , 2 . 83 ( 1 H , m ) , 2 . 59 ( 1 H , m ) , 1 . 62 ( 3 H , d , J = 6 . 7 Hz ) .