1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 61 - 1 . 74 ( 2 H , m ) , 1 . 87 ( 2 H , d ) , 2 . 77 - 2 . 88 ( 1 H , m ) , 3 . 09 ( 2 H , t ) , 3 . 79 ( 2 H , t ) , 4 . 29 ( 2 H , t ) , 4 . 40 ( 2 H , d ) , 6 . 89 ( 2 H , d ) , 7 . 19 ( 2 H , d ) , 7 . 68 ( 1 H , d ) , 8 . 24 ( 1 H , d ) ; m / z = 472 [ M + H ] +.