1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 18 - 1 . 61 ( 6 H , m ) , 1 . 69 - 1 . 79 ( 2 H , m ) , 1 . 94 - 2 . 01 ( 2 H , m ) , 3 . 42 - 3 . 58 ( 2 H , m ) , 4 . 55 - 4 . 68 ( 2 H , m ) , 4 . 94 - 5 . 14 ( 1 H , m ) , 6 . 81 ( 1 H , d , J = 9 . 1 Hz ) , 7 . 78 ( 1 H , d , J = 2 . 6 Hz ) , 7 . 88 ( 1 H , dd , J = 8 . 7 , 2 . 6 Hz ) , 8 . 10 ( 1 H , d , J = 2 . 3 Hz ) , 8 . 27 ( 1 H , d , J = 2 . 3 Hz ) .