1 H NMR ( 400 MHz , CDCl 3 ) δ 8 . 13 ( 1 H , d , J = 9 . 4 Hz ) , 6 . 61 ( 1 H , d , J = 9 . 3 Hz ) , 3 . 61 - 3 . 56 ( 2 H , m ) , 3 . 23 ( 6 H , s ) , 1 . 94 - 1 . 84 ( 2 H , m ) , 1 . 51 - 1 . 40 ( 2 H , m ) , 1 . 36 - 1 . 27 ( 4 H , m ) , 0 . 91 - 0 . 84 ( 3 H , m ) ;