1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 47 ( t , 3 H ) , 1 . 68 - 1 . 83 ( m , 4 H ) , 1 . 96 - 2 . 07 ( m , 4 H ) , 2 . 16 ( m , 3 H ) , 2 . 38 ( t , 2 H ) , 2 . 46 ( m , 1 H ) , 2 . 72 ( s , 3 H ) , 2 . 94 ( br - d , 2 H ) , 2 . 99 ( q , 2 H ) , 4 . 27 ( t , 2 H ) , 6 . 95 ( d , 1 H , J = 6 . 9 Hz ) , 7 . 21 - 7 . 43 ( m , 4 H ) , 8 . 06 ( s , 1 H ) ; MS ( m / e , M +): 499 , 497 , 468 , 280 , 245 , 231