1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 20 - 1 . 62 ( 6 H , m ) , 1 . 63 - 1 . 83 ( 2 H , m ) , 1 . 92 - 2 . 07 ( 2 H , m ) , 2 . 30 ( 3 H , s ) , 3 . 43 - 3 . 58 ( 2 H , m ) , 4 . 48 - 4 . 69 ( 2 H , m ) , 4 . 96 - 5 . 16 ( 1 H , m ) , 6 . 84 ( 1 H , d , J = 8 . 7 Hz ) , 7 . 58 ( 1 H , s ) , 8 . 27 ( 1 H , dd , J = 8 . 7 , 1 . 9 Hz ) , 8 . 85 ( 1 H , d , J = 1 . 9 Hz ) .