1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 72 - 1 . 80 ( m , 4 H ) , 1 . 97 - 2 . 04 ( m , 4 H ) , 2 . 14 ( s , 3 H ) , 2 . 38 ( br t , 2 H , J = 6 . 6 Hz ) , 2 . 47 ( m , 1 H ) , 2 . 94 ( m , 2 H ) , 3 . 88 ( s , 3 H ) , 4 . 37 ( br t , 2 H , J = 7 . 2 Hz ) , 6 . 26 ( m , 1 H ) , 6 . 55 ( m , 1 H ) , 6 . 84 ( br s , 1 H ) , 6 . 97 ( m , 1 H ) , 7 . 21 - 7 . 50 ( m , 6 H ) , 7 . 78 ( m , 1 H ) , MS ( m / e , M +): 457 ( M +- 15 ) , 231 , 209 .