To a suspension of (4-carboxybutyl)triphenyl-phosphonium bromide (1.04 g, 2.35 mmol) in dry tetrahydrofuran (25 mL) at 0° C. under argon was added n-butyl lithium in hexane (1.8 mL of 2.5M, 4.6 mmol). The reaction mixture was stirred for 15 minutes at 0° C. and then a solution of 2-n-butyl-1-(2-chlorophenyl)methyl-1H-imidazol-5-carboxaldehyde [Example 6 (iii)] (0.5 g, 1.81 mmol) in tetrahydrofuran (25 mL) was added dropwise. The mixture was stirred an additional hour at 0° C. and then at ambient temperature for 3 days. Water was added and the mixture was extracted with diethyl ether. The aqueous layer was acidified to pH 3 with aqueous hydrochloric acid solution. The product was extracted into ethyl acetate, washed with water, dried, concentrated, and chromatographed over silica gel eluting with 5-10% methanol in methylene chloride to give 0.24 g of 6-[2-n-butyl-1-{(2-chlorophenyl)methyl}-1H-imidazol-5-yl]-4-hexenoic acid.
