1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 3 . 52 ( 4 H , m ) , 3 . 79 ( 4 H , m ) , 7 . 03 ( 2 H , d ) , 7 . 67 ( 1 H , d ) , 7 . 81 ( 2 H , d ) , 8 . 30 ( 1 H , d ) , 12 . 20 ( 1 H , s ) ; m / z = 393 [ M + H ] +.