1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 74 - 1 . 78 ( 2 H , m ) , 2 . 06 - 2 . 11 ( 2 H , m ) , 3 . 54 - 3 . 60 ( 2 H , m ) , 3 . 93 - 3 . 99 ( 2 H , m ) , 4 . 78 ( 1 H , m ) , 7 . 27 - 7 . 30 ( 1 H , m ) , 7 . 44 ( 1 H , m ) , 7 . 51 - 7 . 57 ( 2 H , m ) , 7 . 65 ( 1 H , d ) , 8 . 26 ( 1 H , d ) , 12 . 97 ( 1 H , s ) ; m / z = 408 [ M + H ] +.