1 H NMR ( CDCl 3 ) δ 8 . 60 ( 1 H , ddd , J = 4 . 9 , 1 . 8 , 1 . 2 Hz ) , 7 . 50 ( 1 H , d , J = 7 . 9 Hz ) , 7 . 22 ( 1 H , dd , J = 7 . 9 , 4 . 9 Hz ) , 7 . 04 - 6 . 95 ( 3 H , m ) , 4 . 66 ( 1 H , dd , J = 14 . 7 , 6 . 1 Hz ) , 4 . 57 ( 1 H , dd , J = 14 . 7 , 5 . 5 Hz ) , 3 . 30 ( 1 H , br s ) , 2 . 65 ( 1 H , m ) , 2 . 37 ( 1 H , m ) , 2 . 20 - 2 . 09 ( 2 H , m ) , 1 . 63 ( 3 H , s ) .