1 H NMR ( 700 . 03 MHz , DMSO - d 6 ) δ 2 . 07 - 2 . 13 ( 2 H , m ) , 2 . 19 - 2 . 21 ( 2 H , m ) , 3 . 13 ( 2 H , d ) , 3 . 98 ( 3 H , s ) , 4 . 43 - 4 . 45 ( 2 H , m ) , 4 . 76 - 4 . 79 ( 1 H , m ) , 6 . 96 ( 1 H , d ) , 7 . 16 ( 2 H , d ) , 7 . 42 - 7 . 44 ( 2 H , m ) , 7 . 67 ( 1 H , d ) , 8 . 17 ( 1 H , s ) , 8 . 29 ( 1 H , d ) , 8 . 56 ( 1 H , d ) ; m / z = 540 [ M + H ] +.