1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 18 ( 3 H , t , J = 7 . 6 Hz ) , 1 . 64 - 1 . 84 ( 3 H , m ) , 1 . 90 - 2 . 09 ( 1 H , m ) , 2 . 59 ( 2 H , q , J = 7 . 6 Hz ) , 3 . 28 ( 2 H , t , J = 6 . 2 Hz ) , 3 . 40 - 3 . 55 ( 2 H , m ) , 3 . 70 - 3 . 89 ( 3 H , m ) , 6 . 86 - 6 . 99 ( 4 H , m ) , 7 . 13 - 7 . 28 ( 4 H , m ) .