1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 68 - 1 . 80 ( 3 H , m ) , 1 . 90 - 2 . 07 ( 1 H , m ) , 2 . 29 ( 3 H , s ) , 3 . 24 - 3 . 30 ( 2 H , m ) , 3 . 47 ( 2 H , q , J = 6 . 4 Hz ) , 3 . 70 - 3 . 89 ( 3 H , m ) , 6 . 84 - 6 . 97 ( 4 H , m ) , 7 . 14 - 7 . 24 ( 4 H , m ) .