The reaction of p-anisaldehyde (I) with N-isopropyl-1,3-diaminopropane (II) in refluxing toluene gives N-anisylidene-N'-isopropyl-1,3-diaminopropane (III), which is then condensed with 2,6-dimethylphenylisocyanate (IV) in refluxing dichloromethane.