1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 55 - 1 . 64 ( m , 2 H ) , 1 . 76 ( m , 2 H ) , 1 . 89 - 1 . 99 ( m , 4 H ) , 2 . 17 ( m , 3 H ) , 2 . 26 ( t , 2 H ) , 2 . 42 ( m , 1 H ) , 2 . 80 ( br - d , 2 H ) , 4 . 39 ( t , 2 H ) , 6 . 94 ( d , 1 H ) , 7 . 24 - 7 . 35 ( m , 6 H ) , 7 . 48 ( m , 1 H ) , 7 . 50 ( m , 2 H ) 7 . 82 ( d , 1 H ) , 7 . 92 ( s , 1 H ) ; MS ( m / e , M +): 521 , 479 , 345 , 304 , 289 , 257 , 231