1 H NMR ( 300 . 1 MHz , DMSO - d 6 ) δ 1 . 27 ( 3 H , t ) , 2 . 49 - 2 . 51 ( 4 H , m ) , 3 . 58 ( 2 H , s ) , 3 . 62 ( 4 H , t ) , 4 . 20 ( 2 H , q ) , 6 . 61 ( 1 H , d ) , 7 . 39 ( 2 H , d ) , 7 . 54 - 7 . 73 ( 4 H , m ) , 8 . 24 ( 1 H , d ) ; m / z = 461 [ M + H ] +.