1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 68 - 1 . 78 ( 2 H , m ) , 2 . 09 - 2 . 13 ( 2 H , m ) , 3 . 01 ( 3 H , s ) , 3 . 13 - 3 . 24 ( 3 H , m ) , 3 . 29 - 3 . 70 ( 4 H , m ) , 4 . 40 - 4 . 43 ( 2 H , m ) , 4 . 78 ( 1 H , t ) , 7 . 14 ( 1 H , dd ) , 7 . 21 ( 1 H , d ) , 7 . 36 ( 1 H , d ) , 7 . 68 ( 1 H , d ) , 7 . 71 ( 1 H , s ) , 8 . 25 ( 1 H , d ) , 11 . 03 ( 1 H , s ) ; m / z = 488 [ M + H ] +.