Synthesis and biological investigations of 3β-aminotropane arylamide derivatives with atypical antipsychotic profile

Recent advances in dopamine D2 receptor ligands in the treatment of neuropsychiatric disorders

Dopamine is a biologically active amine synthesized in the central and peripheral nervous system. This biogenic monoamine acts by activating five types of dopamine receptors (D_1-5 Rs), which belong to the G protein-coupled receptor family. Antagonists and partial agonists of D₂ Rs are used to treat schizophrenia, Parkinson's disease, depression, and anxiety. The typical pharmacophore with high D₂ R affinity comprises four main areas, namely aromatic moiety, cyclic amine, central linker and aromatic/heteroaromatic lipophilic fragment. From the literature reviewed herein, we can conclude that 4-(2,3-dichlorophenyl), 4-(2-methoxyphenyl)-, 4-(benzo[b]thiophen-4-yl)-1-substituted piperazine, and 4-(6-fluorobenzo[d]isoxazol-3-yl)piperidine moieties are critical for high D₂ R affinity. Four to six atoms chains are optimal for D₂ R affinity with 4-butoxyl as the most pronounced one. The bicyclic aromatic/heteroaromatic systems are most frequently occurring as lipophilic appendages to retain high D₂ R affinity. In this review, we provide a thorough overview of the therapeutic potential of D₂ R modulators in the treatment of the aforementioned disorders. In addition, this review summarizes current knowledge about these diseases, with a focus on the dopaminergic pathway underlying these pathologies. Major attention is paid to the structure, function, and pharmacology of novel D₂ R ligands, which have been developed in the last decade (2010-2021), and belong to the 1,4-disubstituted aromatic cyclic amine group. Due to the abundance of data, allosteric D₂ R ligands and D₂ R modulators from patents are not discussed in this review.

One Pot Synthesis and Pharmacological Evaluation of Aryl Substituted Imidazoles as Potential Atypical Antipsychotics

Background:

Second generation or “atypical” antipsychotics demonstrate an improved therapeutic profile over conventional neuroleptics. These are effective in both positive and negative symptoms of the disease and have a lower propensity to induce adverse symptoms.

Objective:

The main objective of the research was in silico design and synthesis of potential atypical antipsychotics with combined antiserotonergic / antidopaminergic effect.

Methods:

A one pot synthesis of aryl substituted imidazole derivatives was carried out in green solvent PEG-400 and the prepared compounds were evaluated for atypical antipsychotic activity in animal models for dopaminergic and serotonergic antagonism. The compounds were designed based on their 3D similarity studies to standard drugs and in silico (docking studies) with respect to 5-HT2A and D2 receptors.

Results:

Results from the docking studies with respect to 5-HT2A and D2 receptors suggested a potential atypical antipsychotic profile for the test compounds. Theoretical ADME profiling of the compounds based on selected physicochemical parameters suggested an excellent compliance with Lipinski’s rules. The potential of these compounds to penetrate the blood brain barrier (log BB) was computed through an online software program and the values obtained for the compounds suggested a good potential for brain permeation. Reversal of apomorphine induced mesh climbing behaviour coupled with inactivity in the stereotypy assay indicates antidopaminergic effect and a potential atypical profile for the test compounds 1-5. Further, the activity of compounds in DOI assay indicated a 5-HT2 antagonistic profile (5-HT2 antagonism).

Conclusion:

Compound 5 emerged as important lead compound showing combined antidopaminergic and antiserotonergic (5-HT2A) activity with a potential atypical antipsychotic profile.