The condensation of glutamic acid (I) with 3,4-dichlorobenzoyl chloride (II) by means of Na2CO3 in water gives N-(3,4-dichlorobenzoyl)glutamic acid (III), which is treated with acetic anhydride in refluxing isopropyl ether to afford N-(3,4-dichlorobenzoyl)glutamic anhydride (IV). Finally, this compound is treated with dipentylamine (V) in water.