1 H NMR ( 300 MHz , CDCl 3 ) δ : 8 . 44 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 67 - 7 . 55 ( m , 7 H ) , 7 . 42 - 7 . 36 ( m , 1 H ) , 7 . 03 ( s , 1 H ) , 4 . 30 ( d , J = 6 . 6 Hz , 2 H ) , 4 . 15 ( s , 3 H ) , 2 . 33 - 2 . 27 ( m , 1 H ) , 1 . 17 ( d , J = 6 . 8 Hz , 6 H ) .