To a solution of 1.2 ml hexamethylphosphoramide and 6.7 ml 1.75M lithium diisopropylamide in 9 ml tetrahydrofuran at 0° C. under nitrogen was slowly added a solution of 1.00 g 3,5-dichloro-4-methylbenzoic acid in 3 ml tetrahydrofuran. After 1 hr the solution was cooled to -78° C. and 1.00 g 5-(5-bromopentyl)-3-methylisoxazole was added. The reaction mixture was stirred at room temperature for 19 hrs and worked up by acid-base extraction to give 1.3 g crude acid product. The latter was treated with 1 ml ethyl iodide and 4.9 g potassium carbonate in 10 ml dimethylformamide, stirred 12 hrs at room temperature. Extraction with ether and washing with water provided 1 g of ethyl 3,5-dichloro-4-[6-(3-methyl-5-isoxazolyl)hexyl]benzoate suitable for subsequent reactions.
