1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 07 ( t , 3 H , J = 7 . 0 Hz ) , 1 . 39 ( t , 3 H , J = 7 . 2 Hz ) , 1 . 71 ( d , 3 H , J = 6 . 3 Hz ) , 2 . 39 ( s , 3 H ) , 2 . 78 ( s , 3 H ) , 3 . 18 ( q , 2 H , J = 7 . 0 Hz ) , 4 . 40 ( q , 2 H , J = 7 . 2 Hz ) , 5 . 47 ( q , 1 H , J = 6 . 3 Hz ) , 7 . 23 ( d , 2 H , J = 7 . 8 Hz ) , 7 . 35 ( d , 2 H , J = 7 . 8 Hz ) ;