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General procedure: To L1 (2.00 g, 13.6 mmol) dissolved in acetonitrile (60 mL) was added potassium carbonate (18.8 g, 136 mmol). The resulting solution was heated at reflux temperature for 30 min and to the hot solution was added 1,n-dibromoalkane (48.0 mmol, n=3, 4, 6 or 8). The reaction mixture was then stirred at reflux temperature for a further 24 . After cooling, the inorganic solids were removed by filtration and the solvent was removed under reduced pressure to afford an oil, which was purified by column chromatography on silica gel (initially at a ratio of petroleum ether:ethyl acetate 80:20, followed by the ratio of 60:40). This gave the products L2A-D and L3A-D.