1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 85 ( s , 1 H ) , 8 . 11 ( d , J = 2 . 0 Hz , 1 H ) , 7 . 38 ( d , J = 2 . 0 Hz , 1 H ) , 4 . 07 - 4 . 13 ( m , 2 H ) , 4 . 04 ( s , 3 H ) , 1 . 41 - 1 . 47 ( m , 3 H ) .