1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 07 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 39 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 67 ( d , 3 H , J = 6 . 3 Hz ) , 2 . 78 ( s , 3 H ) , 3 . 16 ( br , 2 H ) , 3 . 74 ( s , 3 H ) , 4 . 40 ( q , 2 H , J = 7 . 1 Hz ) , 5 . 14 ( q , 1 H , J = 6 . 3 Hz ) , 6 . 87 ( dd , 1 H , J = 4 . 4 , 8 . 9 Hz ) , 7 . 09 - 7 . 19 ( m , 2 H ) ;