1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 73 ( 2 H , m ) , 1 . 92 ( 2 H , m ) , 2 . 98 ( 1 H , m ) , 3 . 13 ( 2 H , m ) , 3 . 84 ( 3 H , s ) , 4 . 44 ( 2 H , m ) , 7 . 44 ( 2 H , d ) , 7 . 68 ( 1 H , d ) , 7 . 91 ( 2 H , d ) , 8 . 27 ( 1 H , d ) ; m / z = 406 [ M + H ] +.