1 H NMR ( 400 . 1 MHz , DMSO - d 6 ) δ 1 . 53 - 1 . 61 ( 2 H , m ) , 1 . 86 ( 2 H , m ) , 2 . 74 - 2 . 83 ( 2 H , m ) , 2 . 96 ( 2 H , m ) , 7 . 34 ( 1 H , m ) , 7 . 83 ( 1 H , m ) , 8 . 43 ( 1 H , m ) , 8 . 69 ( 1 H , d ) .