1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 11 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 39 ( t , 3 H , J = 7 . 2 Hz ) , 1 . 62 ( d , 3 H , J = 6 . 5 Hz ) , 2 . 19 ( s , 3 H ) , 2 . 78 ( s , 3 H ) , 3 . 25 ( q , 2 H , J = 7 . 1 Hz ) , 4 . 40 ( q , 2 H , J = 7 . 2 Hz ) , 5 . 14 ( q , 1 H , J = 6 . 5 Hz ) , 7 . 20 - 7 . 39 ( m , 4 H ) ;