1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 65 - 1 . 81 ( m , 4 H ) , 1 . 88 - 1 . 99 ( m , 4 H ) , 2 . 18 ( s , 3 H ) , 2 . 24 ( t , 2 H ) , 2 . 44 ( m , 1 H ) , 2 . 83 ( brd , 2 H ) , 4 . 33 ( t , 2 H ) , 6 . 96 ( d , 1 H , J = 7 . 5 Hz ) , 7 . 21 - 7 . 28 ( m , 5 H ) , 7 . 36 ( d , 1 H , 7 . 8 Hz ) , 7 . 53 ( m , 2 H ) , 7 . 69 - 7 . 77 ( m , 3 H ) ; MS ( m / e , M +): 505