1 H NMR ( 400 MHz , CDCl 3 ) δ = 8 . 12 ( dd , J = 8 . 2 , 0 . 8 Hz , 2 H ) , 7 . 99 ( s , 2 H ) , 7 . 96 ( s , 2 H ) , 7 . 65 - 7 . 48 ( m , 10 H ) , 7 . 38 - 7 . 33 ( m , 2 H ) , 7 . 26 - 7 . 24 ( m , 4 H ) , 6 . 22 ( d , J = 17 . 6 Hz , 2 H ) , 5 . 95 - 5 . 84 ( m , 2 H ) , 5 . 71 ( dd , J = 50 . 8 , 3 . 9 Hz , 2 H ) 5 . 73 - 5 . 71 ( m , 2 H ) , , 4 . 88 - 4 . 77 ( m , 4 H ) , 4 . 59 - 4 . 38 ( m , 8 H ) , 4 . 19 ( m , 2 H ) .