1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 16 ( 3 H , t , J = 7 . 7 Hz ) , 1 . 64 - 1 . 84 ( 3 H , m ) , 1 . 91 - 2 . 11 ( 1 H , m ) , 2 . 60 ( 2 H , q , J = 7 . 5 Hz ) , 3 . 23 - 3 . 28 ( 2 H , m ) , 3 . 38 - 3 . 57 ( 2 H , m ) , 3 . 70 - 3 . 88 ( 3 H , m ) , 6 . 80 ( 1 H , dd , J = 7 . 7 , 2 . 1 Hz ) , 6 . 88 - 6 . 95 ( 3 H , m ) , 7 . 00 ( 1 H , d , J = 6 . 8 Hz ) , 7 . 20 ( 2 H , d , J = 8 . 3 Hz ) , 7 . 29 ( 1 H , t , J = 7 . 9 Hz ) .