1 H NMR ( 399 . 9 MHz , CDCl 3 ) δ 2 . 57 - 2 . 70 ( 4 H , m ) , 3 . 61 - 3 . 73 ( 6 H , m ) , 6 . 65 ( 1 H , t ) , 7 . 05 ( 1 H , d ) , 7 . 45 - 7 . 51 ( 4 H , m ) , 7 . 93 ( 1 H , d ) ; m / z = 414 [ M + H ] +.