1 H NMR ( 300 MHz , CDCl 3 ) 8 . 55 ( br s , 1 H ) , 4 . 52 ~ 4 . 42 ( m , 1 H ) , 3 . 71 ~ 3 . 54 ( m , 2 H ) , 2 . 35 ~ 1 . 916 ( m , 6 H ) , 1 . 63 ~ 1 . 61 ( m , 2 H ) , 1 . 27 ( m , 8 ) , 0 . 86 ( t , J = 7 . 6 , 3 H ) .