1 H NMR ( CDCl 3 ) δ 8 . 62 ( 1 H , d , J = 5 . 0 Hz ) , 7 . 50 ( 1 H , d , J = 7 . 6 Hz ) , 7 . 41 ( 1 H , dd , J = 8 . 6 , 6 . 0 Hz ) , 7 . 10 - 7 . 25 ( 3 H , m ) , 6 . 99 ( 1 H , td , J = 8 . 3 , 2 . 6 Hz ) , 4 . 54 - 4 . 67 ( 2 H , m ) , 3 . 46 ( 1 H , d , J = 8 . 0 Hz ) , 3 . 22 - 3 . 39 ( 4 H , m ) , 2 . 90 ( 1 H , d , J = 12 . 8 Hz ) , 2 . 59 - 2 . 74 ( 1 H , m ) , 2 . 14 - 2 . 27 ( 3 H , m ) , 1 . 45 ( 3 H , s ) .