1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 59 - 1 . 75 ( m , 4 H ) , 1 . 90 ( brt , 2 H ) , 2 . 02 ( m , 2 H ) 2 . 16 ( s , 3 H ) , 2 . 32 ( t , 2 H ) , 2 . 42 ( m , 1 H ) , 2 . 68 ( s , 3 H ) , 2 . 84 ( br , 2 H ) , 4 . 39 ( t , 2 H ) , 6 . 92 ( d , 1 H , J = 7 . 2 Hz ) , 7 . 23 - 7 . 39 ( m , 3 H ) , 7 . 50 - 7 . 54 ( m , 4 H ) , 7 . 70 ( d , 1 H , J = 8 . 1 Hz ) , 7 . 78 ( m , 2 H ) ; MS ( m / e , M +): 467