1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 61 ( m , 2 H ) , 1 . 73 ( brd , 2 H ) , 1 . 86 - 2 . 03 ( m , 4 H ) , 2 . 16 ( s , 3 H ) , 2 . 22 ( t , 2 H ) , 2 . 39 ( m , 1 H ) , 2 . 78 ( s , 3 H ) , 2 . 83 ( brd , 2 H ) , 4 . 37 ( t , 2 H ) , 6 . 93 ( d , 1 H , J = 7 . 5 Hz ) , 7 . 21 - 7 . 37 ( m , 3 H ) , 7 . 51 - 7 . 55 ( m , 4 H ) , 7 . 78 ( m , 2 H ) , 8 . 02 ( s , 1 H ) ; MS ( m / e , M +): 546