1 H NMR ( 399 . 9 MHz , CDCl 3 ) δ 1 . 37 ( 6 H , s ) , 2 . 61 ( 4 H , t ) , 3 . 56 ( 4 H , t ) , 6 . 98 - 7 . 02 ( 3 H , m ) , 6 . 98 - 7 . 24 ( 1 H , m ) , 7 . 49 - 7 . 53 ( 2 H , m ) , 7 . 86 - 7 . 89 ( 1 H , m ) ; m / z = 391 [ M + H ] +.