1 H NMR ( 300 MHz , CDCl 3 ) δ 8 . 08 ( d , J = 5 . 1 Hz , 1 H ) , 7 . 36 - 7 . 48 ( m , 5 H ) , 6 . 71 ( d , J = 5 . 1 Hz , 1 H ) , 5 . 02 ( s , 2 H ) , 4 . 40 - 4 . 48 ( m , 4 H ) , 1 . 41 ( t , J = 7 . 2 Hz , 3 H ) .