1 H NMR ( 300 MHz , CDCl 3 ) δ 7 . 11 ( d , 1 H , J = 2 . 1 ) , 7 . 02 ( dd , 1 H , J = 8 . 4 ) , 6 . 92 ( dd , 1 H , J = 10 . 2 ) , 6 . 83 ( m , 1 H ) , 6 . 09 ( d , 1 H , J = 10 . 2 ) , 5 . 53 ( m , 1 H ) , 4 . 89 ( m , 2 H ) , 4 . 84 ( m , 1 H ) , 3 . 90 ( s , 3 H ) , 3 . 40 ( m , 1 H ) , 3 . 07 ( m , 1 H ) , 2 . 53 ( m , 2 H ) , 2 . 41 ( m , 2 H )