Abstract: Piperazine or piperidine compounds useful for treating neurodegenerated diseases characterized by the lack of dopamine neurons activity or for imaging the dopamine neurons are provided. The piperazine or piperadine compounds are characterized by the formula:Formula I wherein: A is oxygen; n is an integer of 1 to 6; X and Y can be the same or different and are hydrogen, halogen, nitro, alkyl or halalkyl, Z is carbon or nitrogen; and &phgr; is phenyl, naphthyl, thienyl or pyridinyl. When Z is carbon, R is hydrogen, cyano, hydroxy, —COOCH3, —CH20H or —COOH; R1 is 4-fluorophenyl, 4-chlorophenyl, 4-trifluoromethyl, 3-trifluoromethyl-4 -chlorophenyl 4-bromophenyl), 4-(2-keto-1-benzimidazolinyl or 1-phenyl 1, 3, 8-triazaspiro [4,5] decan-4-one.

Abstract: Diamine compounds useful for treating neurodegenerated diseases characterized by the lack of dopamine neurons activity or for imaging the dopamine neurons are provided.

Abstract: Diamine compounds useful for treating neurodegenerated diseases characterized by the lack of dopamine neurons activity or for imaging the dopamine neurons are provided. The diamine compounds or serotonin are characterized by the formula: ##STR1## wherein: l, m and n can be the same or different and are an integer of 1 to 6; X, Y and Z can be the same or different and are hydrogen, halo, haloalkyl, (C.sub.1 -C.sub.6) alkyl, aryl, (C.sub.1 -C.sub.6) alkoxy, N-alkyl, (C.sub.2 -C.sub.6) acyloxy, N-alkylene, --SH, or --SR, wherein R is from the same group as R.sub.1 and R.sub.2 and can be the same or different than R.sub.1 and R.sub.2, amino, nitro, cyano, hydroxy, --C(.dbd.O) OR.sub.6, --C(.dbd.O) NR.sub.5 R.sub.4, NR.sub.3 R.sub.2, or S(.dbd.O).sub.k R.sub.1 wherein .sub.k is 1 or 2, and R.sub.4 to R.sub.6 are independently hydrogen or (C.sub.1 -C.sub.6) alkyl;R.sub.1, and R.sub.2 can be the same or different and are hydrogen, (C.sub.1 -C.sub.6) alkyl, hydroxyalkyl or mercaptoalkyl, --C(.dbd.O) OR.sub.