1 H - NMR ( 300 MHz , CDCl 3 ) σ 1 . 11 ( t , 3 H , J = 7 . 0 Hz ) , 1 . 39 ( t , 3 H , J = 7 . 1 Hz ) , 1 . 62 ( d , 3 H , J = 6 . 2 Hz ) , 2 . 13 ( s , 3 H ) , 2 . 31 ( s , 3 H ) , 2 . 77 ( s , 3 H ) , 3 . 15 - 3 . 35 ( m , 2 H ) , 4 . 40 ( q , 2 H , J = 7 . 1 Hz ) , 5 . 15 ( q , 1 H , J = 6 . 2 Hz ) , 7 . 01 ( s , 1 H ) , 7 . 14 ( s , 2 H ) ;