1 H NMR ( 400 MHz , CDCl 3 ) δ 4 . 20 - 4 . 10 ( m , 1 H ) , 3 . 90 - 3 . 80 ( m , 1 H ) , 3 . 45 - 3 . 35 ( m , 1 H ) , 3 . 30 - 3 . 18 ( m , 1 H ) , 3 . 14 - 3 . 04 ( m , 2 H ) , 2 . 85 ( s , 3 H ) , 2 . 66 - 2 . 55 ( m , 2 H ) , 2 . 36 - 2 . 28 ( m , 1 H ) , 1 . 98 - 1 . 90 ( m , 2 H ) , 1 . 55 - 1 . 35 ( m , 2 H )