A solution of p-(4-phenylbutoxy)benzoyl chloride prepared from 1 g of p-(phenylbutoxy)benzoic acid and 2 ml of oxalyl chloride in methylene chloride was added to a solution of 0.6 g of ethyl 6-(o-aminophenyl)hexanate obtained in Reference Example 17 in 10 ml of pyridine at temperature less than -30° C. The mixture was stirred at room temperature overnight and concentrated under reduced pressure. Toluene was added to the residue. The mixture was washed with diluted hydrochloric acid and then with water and dried over anhydrous magnesium sulfate. The systems was concentrated under reduced pressure to obtain 1.0 g of oily ethyl 6-[o-[p-(4-phenylbutoxy)benzamido]phenyl]hexanate.
