1 H NMR ( 300 MHz , DMSO - d 6 ) δ 1 . 73 - 1 . 79 ( 3 H , m ) , 1 . 93 - 2 . 08 ( 1 H , m ) , 3 . 25 - 3 . 29 ( 2 H , m ) , 3 . 40 - 3 . 55 ( 2 H , m ) , 3 . 72 - 3 . 91 ( 3 H , m ) , 6 . 95 - 7 . 10 ( 3 H , m ) , 7 . 21 - 7 . 36 ( 3 H , m ) , 7 . 63 ( 1 H , d , J = 9 . 1 Hz ) .