1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 75 - 1 . 82 ( 2 H , m ) , 1 . 84 - 1 . 90 ( 2 H , m ) , 2 . 66 - 2 . 70 ( 1 H , m ) , 2 . 80 - 2 . 85 ( 4 H , m ) , 3 . 79 ( 3 H , s ) , 3 . 80 - 3 . 83 ( 2 H , s ) , 4 . 06 ( 2 H , t ) , 6 . 90 ( 2 H , d ) , 7 . 21 ( 2 H , d ) , 7 . 34 ( 1 H , s ) , 7 . 57 ( 2 H , s ) , 7 . 77 - 7 . 80 ( 1 H , m ) , 7 . 94 ( 1 H , d ) ; m / z = 471 [ M + H ] +.