1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 66 - 1 . 79 ( 3 H , m ) , 1 . 93 - 2 . 04 ( 1 H , m ) , 3 . 23 - 3 . 28 ( 2 H , m ) , 3 . 41 - 3 . 52 ( 2 H , m ) , 3 . 70 - 3 . 76 ( 1 H , m ) , 3 . 78 - 3 . 87 ( 2 H , m ) , 4 . 74 ( 2 H , q , J = 8 . 8 Hz ) , 6 . 99 ( 2 H , d , J = 8 . 7 Hz ) , 7 . 16 ( 2 H , d , J = 8 . 7 Hz ) .