The condensation of 1-(2-pyrimidinyl)piperazine (I) with 3-chloro-1-cyanopropane (II) by means of Na2CO3 in n-butanol gives 4-(2-pyrimidinyl)-1-(3-cyanopropyl)piperazine (III). This product is reduced with LiAlH4 or with H2 and Raney-Ni yielding 4-(2-pyrimidinyl)-1-(4-aminobutyl)piperazine (IV), which is finally condensed with 8-oxaspiro[4.5]decane-7,9-dione-(3,3-tetramethylene-glutaric anhydride) (V) in pyridine.