1 H NMR ( CDCl 3 ) δ : 7 . 26 - 7 . 36 ( m , 5 H ) , 6 . 91 ( s , 1 H ) , 6 . 73 ( s , 1 H ) , 3 . 7 - 3 . 8 ( bs , 2 H ) , 3 . 33 ( bs , 2 H ) , 2 . 8 ( s , 3 H ) , 2 . 27 ( s , 3 H ) , 1 . 25 - 1 . 82 ( m , 13 H ) .