1 H NMR ( 500 MHz , CDCl 3 ) : 7 . 89 - 6 . 53 ( 19 H , m ) , 5 . 82 ( 2 H , s ) , 4 . 26 ( 1 H , d ) , 4 . 14 - 4 . 10 ( 1 H , m ) , 3 . 19 ( 3 H , s ) , 2 . 40 ( 3 H , m ) , 1 . 35 - 1 . 21 ( 6 H , m ) , 1 . 14 ( 9 H , s ) , 0 . 97 - 0 . 9 ( 4 H , m ) , - 0 . 34 ( 3 H , t ) .