1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 65 - 1 . 88 ( 3 H , m ) , 1 . 88 - 2 . 10 ( 1 H , m ) , 2 . 34 ( 3 H , s ) , 3 . 24 - 3 . 29 ( 2 H , m ) , 3 . 41 - 3 . 60 ( 2 H , m ) , 3 . 73 - 3 . 91 ( 3 H , m ) , 7 . 17 - 7 . 35 ( 4 H , m ) , 7 . 47 - 7 . 64 ( 4 H , m ) .