1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 66 - 1 . 81 ( 3 H , m ) , 1 . 90 - 2 . 10 ( 1 H , m ) , 2 . 34 ( 3 H , s ) , 3 . 24 - 3 . 30 ( 2 H , m ) , 3 . 42 - 3 . 54 ( 2 H , m ) , 3 . 76 - 3 . 89 ( 3 H , m ) , 7 . 27 - 7 . 35 ( 4 H , m ) , 7 . 38 - 7 . 47 ( 4 H , m ) .