Synthesis of dicationic diarylpyridines as nucleic-acid binding agents

Area of Science:

• Medicinal Chemistry
• Organic Synthesis
• Molecular Biology

Background:

• Pyridine derivatives are explored for their potential biological activities.
• Bis-imidazolylphenylpyridine structures offer unique binding capabilities.

Purpose of the Study:

• To synthesize novel bis-imidazolylphenylpyridine compounds.
• To evaluate their DNA and RNA binding affinities.
• To assess their biological activities, including anti-HIV-1 and anti-parasitic potential.

Main Methods:

• Multi-step organic synthesis from substituted bromoacetophenone and bromophenylacetonitrile.
• DNA (poly dA·dT) and RNA (poly A·U) binding assays.
• Topoisomerase II inhibition assays.
• In vivo testing in immuno-suppressed rat models for anti-parasitic activity.
• In vitro anti-HIV-1 assays in primary lymphocytes.

Main Results:

• Synthesized compounds 7, 8, 9, 13, and 18 with varying synthetic routes.
• Established a binding order to poly dA·dT (7 > 13 > 18 > 8 > 9) and poly A·U (7 > 13 > 8 > 9).
• Compound 18 showed minimal binding to RNA.
• Only compound 7 inhibited topoisomerase II at millimolar concentrations.
• Compounds demonstrated modest anti-HIV-1 activity and selectivity.
• Tested compounds showed modest activity against Pneumonocystis carinii with moderate toxicity.

Conclusions:

• Novel bis-imidazolylphenylpyridine derivatives were successfully synthesized.
• Binding affinities vary significantly between DNA and RNA models.
• Compound 7 exhibits promising topoisomerase II inhibitory and anti-HIV-1 activities.
• Further research is warranted to optimize efficacy and reduce toxicity for therapeutic applications.