1 H NMR ( CDCl 3 ) δ 8 . 19 ( 1 H , d , J = 1 . 8 Hz ) , 7 . 71 ( 1 H , d , J = 1 . 8 Hz ) , 5 . 80 ( 1 H , ddt , J = 17 . 1 , 10 . 4 , 6 . 1 Hz ) , 5 . 16 ( 1 H , br d , J = 17 . 1 Hz ) , 5 . 10 ( 1 H , br d , J = 10 . 4 Hz ) , 4 . 23 ( 1 H , m ) , 2 . 41 - 2 . 25 ( 2 H , m ) , 2 . 37 ( 3 H , s ) , 2 . 06 - 1 . 90 ( 2 H , m ) .