1 H NMR ( 499 . 8 MHz , DMSO - d 6 ) δ 1 . 85 - 1 . 91 ( 2 H , sm , 2 . 65 ( 2 H , t ) , 2 . 75 ( 2 H , t ) , 3 . 73 - 3 . 77 ( 6 H , m ) , 7 . 46 ( 2 H , d ) , 7 . 50 ( 1 H , d ) , 7 . 58 ( 2 H , d ) , 8 . 23 ( 1 H , d ) ; m / z = 445 [ M + H ] +.