To an acetonitrile solution of 2- or 3-thiophene aminoethyl compounds 6 (1 eq) was added either an alkyl methanesulfonate or alkyl halide (e.g. 4-(4-nitrophenyl)-1-butyl methanesulfonate [prepared by reacting 4-(4-nitrophenyl)butane-1-ol with methanesulfonyl chloride in methylene chloride and triethylamine and isolated as a crystalline solid from ether/hexane], 1-(2-chloroethoxy)-4-nitrobenzene or 1-(3-chloropropoxy)-4-nitrobenzene [prepared by reacting 4-nitrophenol (1 eq) with 1-bromo-3-chloropropane (1.5 eq) in methyl ethyl ketone with K2CO3 (2 eq) present and isolated as a yellow oil that was crystallized from ether/hexane, mp 37.5°-38.5° C.] (1.5-2.0 eq) and K2CO3 (5 eq) [for the chloro compounds, Nal (1.4-2 eq) was added]. The mixture was refluxed under nitrogen for 16-18 hours. After the solvent had been removed in vacuo, the oily solid was mixed as a slurry in water and extracted with methylene chloride. The combined methylene chloride extract was washed with water and brine and dried (Na2SO4). Solvent removal produced the crude product that was purified by flash silica gel chromatography using a mixture of ethyl acetate in hexane.
