1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 72 - 1 . 84 ( m , 4 H ) , 2 . 04 ( m , 2 H ) , 2 . 18 ( s , 3 H ) , 2 . 24 ( t , 2 H ) , 2 . 51 ( m , 1 H ) , 2 . 70 ( m , 2 H ) , 3 . 13 ( brd , 2 H ) , 4 . 38 ( t , 2 H ) , 6 . 93 ( d , 1 H , J = 8 . 4 Hz ) , 7 . 07 - 7 . 29 ( m , 7 H ) , 7 . 36 - 7 . 42 ( m , 2 H ) , 7 . 71 ( m , 2 H ) , 8 . 55 ( d , 1 H ) ; MS ( m / e , M +): 468