1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 64 - 1 . 83 ( 3 H , m ) , 1 . 92 - 2 . 07 ( 1 H , m ) , 3 . 14 ( 2 H , t , J = 8 . 7 Hz ) , 3 . 24 - 3 . 27 ( 2 H , m ) , 3 . 38 - 3 . 56 ( 2 H , m , J = 5 . 7 Hz ) , 3 . 70 - 3 . 86 ( 3 H , m ) , 4 . 56 ( 2 H , t , J = 8 . 7 Hz ) , 6 . 38 - 6 . 51 ( 2 H , m ) , 6 . 91 ( 2 H , d , J = 8 . 7 Hz ) , 7 . 12 - 7 . 24 ( 3 H , m ) .