1 H NMR ( 300 MHz , DMSO - d 6 ) δ 0 . 83 - 0 . 99 ( 3 H , m ) , 1 . 49 ( 1 H , q , J = 12 . 3 Hz ) , 1 . 70 - 2 . 17 ( 2 H , m ) , 3 . 04 - 3 . 25 ( 3 H , m ) , 3 . 37 - 3 . 63 ( 1 H , m ) , 3 . 74 - 3 . 87 ( 6 H , m ) , 6 . 52 ( 1 H , dt , J = 9 . 1 , 3 . 2 Hz ) , 6 . 87 - 6 . 98 ( 3 H , m ) , 7 . 15 - 7 . 26 ( 3 H , m ) .