1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 08 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 39 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 71 ( d , 3 H , J = 6 . 2 Hz ) , 2 . 78 ( s , 3 H ) , 3 . 19 ( m , 2 H ) , 3 . 83 ( s , 3 H , ) , 4 . 40 ( q , 2 H , J = 7 . 1 Hz ) , 5 . 50 ( q , 1 H , J = 6 . 2 Hz ) , 6 . 99 - 7 . 06 ( m , 3 H ) , 7 . 33 ( dd , 1 H , J = 7 . 9 , 7 . 9 Hz ) ;