1 H NMR ( 499 . 802 MHz , DMSO - d 6 ) δ 2 . 55 - 2 . 62 ( 4 H , m ) , 3 . 61 - 3 . 66 ( 4 H , m ) , 3 . 68 ( 2 H , s ) , 7 . 26 - 7 . 32 ( 1 H , m ) , 7 . 49 ( 1 H , d ) , 7 . 59 ( 1 H , d ) , 7 . 76 - 7 . 82 ( 1 H , m ) , 8 . 25 ( 1 H , d ) , 8 . 52 ( 1 H , d ) ; m / z = 364 [ M + H ] +.