1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 40 - 1 . 45 ( m , 2 H ) , 1 . 72 ( m , 2 H ) , 1 . 85 - 2 . 04 ( m , 4 H ) , 2 . 14 ( t , 2 H ) , 2 . 17 ( s , 3 H ) , 2 . 35 ( m , 1 H ) , 2 . 40 ( s , 3 H ) , 2 . 43 ( s , 3 H ) , 2 . 74 ( brd , 2 H ) , 4 . 38 ( t , 2 H ) , 6 . 91 ( d , 1 H , J = 7 . 6 Hz ) , 7 . 17 - 7 . 28 ( m , 2 H ) , 7 . 47 ( d , 1 H , J = 7 . 8 Hz ) , 7 . 60 ( d , 2 H , J = 10 . 9 Hz ) , 7 . 78 - 7 . 85 ( m , 2 H ) , 7 . 92 ( d , 2 H , J = 8 . 1 Hz ) ; MS ( m / e , M +): 505