1 H NMR ( 499 . 8 MHz , DMSO - d 6 ) δ 1 . 86 - 1 . 92 ( 2 H , m ) , 2 . 67 ( 2 H , t ) , 2 . 79 - 2 . 83 ( 2 H , m ) , 3 . 27 ( 3 H , s ) , 3 . 74 ( 2 H , t ) , 3 . 78 ( 2 H , t ) , 4 . 03 ( 2 H , s ) , 7 . 51 ( 1 H , d ) , 7 . 55 - 7 . 60 ( 3 H , m ) , 7 . 95 ( 1 H , d ) , 8 . 23 ( 1 H , d ) ; m / z = 455 [ M + H ] +.