1 H - NMR ( 400 MHz , CDCl 3 ) δ : 7 . 63 ( 1 H , d , J = 8 . 8 Hz ) , 7 . 55 ( 1 H , s ) , 7 . 35 ( 2 H , t , J = 7 . 6 Hz ) , 7 . 26 ( 3 H , m ) , 7 . 15 ( 2 H , m ) , 6 . 97 ( 4 H , m ) , 6 . 91 ( 2 H , m ) , 7 . 78 ( 1 H , d , J = 8 . 8 Hz ) , 5 . 16 ( 2 H , s ) , 4 . 68 ( 2 H , t , J = 8 . 8 Hz ) , 3 . 20 ( 2 H , t , J = 8 . 8 Hz ) , 2 . 37 ( 3 H , s ) .