1 H NMR ( CDCl 3 ) δ : 7 . 57 - 7 . 59 ( m , 2 H ) , 7 . 29 - 7 . 38 ( m , 3 H ) , 6 . 94 ( brs , 1 H ) , 6 . 82 ( s , 1 H ) , 6 . 49 ( s , 1 H ) , 3 . 86 - 3 . 92 ( m , 2 H ) , 3 . 47 - 3 . 51 ( m , 2 H ) , 2 . 42 - 2 . 45 ( m , 1 H ) , 2 . 21 ( s , 3 H ) , 0 . 83 - 1 . 82 ( m , 10 H ) .