1 H NMR ( 300 MHz , DMSO - d 6 ) δ 3 . 41 - 3 . 54 ( 2 H , m ) , 3 . 83 ( 3 H , s ) , 4 . 60 - 4 . 74 ( 2 H , m ) , 6 . 75 ( 1 H , t , J = 7 . 0 Hz ) , 7 . 22 - 7 . 36 ( 3 H , m ) , 7 . 45 - 7 . 55 ( 1 H , m ) , 7 . 64 - 7 . 90 ( 6 H , m ) .