1 H NMR ( 499 . 8 MHz , DMSO - d 6 ) δ 2 . 58 ( 4 H , t ) , 3 . 22 ( 4 H , t ) , 3 . 67 ( 2 H , s ) , 7 . 54 ( 1 H , s ) , 7 . 57 ( 2 H , d ) , 7 . 72 - 7 . 74 ( 1 H , m ) , 7 . 83 ( 2 H , d ) , 7 . 93 ( 1 H , d ) ; m / z = 387 [ M + H ] +.