1 H NMR / CDCl 3 　( ppm ) : 0 . 5 ( 2 H , m ) , 1 . 0 ( 12 H , 2 d ) , 1 . 53 ( 2 H , quint . ) , 2 . 61 ( 3 H , s ) , 2 . 98 ( 2 H , t ) , 3 . 21 ( 1 H , sept ) , 3 . 32 ( 1 H , sept ) , 3 . 48 ( 9 H , s ) .