1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 81 ( m , 4 H ) , 2 . 00 ( m , 4 H ) , 2 . 14 ( s , 3 H ) , 2 . 37 ( m , 2 H ) , 2 . 39 ( s , 3 H ) , 2 . 40 ( s , 3 H ) , 2 . 48 ( m , 1 H ) , 2 . 97 ( m , 2 H ) , 3 . 85 ( s , 3 H ) , 4 . 31 ( br t , 2 H , J = 7 . 4 Hz ) , 6 . 24 ( br t , 1 H , J = 2 . 9 Hz ) , 6 . 50 ( m , 1 H ) , 6 . 81 ( br s , 1 H ) , 6 . 97 ( m , 1 H ) , 7 . 20 - 7 . 27 ( m , 2 H ) , 7 . 35 ( m , 1 H ) , 7 . 43 ( m , 2 H ) , 7 . 55 ( br s , 1 H ) ; MS ( m / e , M +): 483 ( M +), 252 , 231 , 70 .