1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 03 ( t , 3 H , J = 7 . 3 Hz ) , 1 . 39 ( t , 3 H , J = 6 . 9 Hz ) , 1 . 71 ( d , 3 H , J = 6 . 1 Hz ) , 2 . 34 ( s , 6 H ) , 2 . 78 ( s , 3 H ) , 3 . 19 ( q , 2 H , J = 7 . 3 Hz ) , 4 . 40 ( q , 2 H , J = 6 . 9 Hz ) , 5 . 50 ( q , 1 H , J = 6 . 1 Hz ) , 7 . 07 ( m , 3 H ) ;