1 H NMR ( 399 . 1 MHz , DMSO - d 6 ) δ 2 . 70 ( 2 H , m ) , 3 . 91 ( 2 H , m ) , 4 . 29 ( 2 H , m ) , 6 . 44 ( 1 H , m ) , 7 . 41 ( 1 H , m ) , 7 . 69 ( 1 H , d ) , 7 . 89 ( 1 H , m ) , 8 . 30 ( 1 H , d ) , 8 . 50 ( 1 H , m ) , 8 . 74 ( 1 H , m ) ; m / z = 347 [ M + H ] +.