Tetracyclic pyridazines as potential psychopharmacological agents

Area of Science:

• Medicinal Chemistry
• Neuroscience
• Organic Synthesis

Background:

• The Z isomer of chlorprothixene is significantly more pharmacologically active than its E isomer.
• Developing stereoselective syntheses for related compounds is of therapeutic interest.

Purpose of the Study:

• To synthesize novel compounds based on the chlorprothixene scaffold.
• To evaluate the potential of these compounds as inhibitors of neurotransmitter uptake.
• To investigate structure-activity relationships, including modifications to the central ring system and side chain.

Main Methods:

• Stereoselective synthesis of chlorprothixene analogs.
• Modification of the core structure, including sulfur bridge replacement and removal.
• Preparation of peri amino derivatives.
• In vitro and in vivo neurotransmitter uptake inhibition assays.
• Spiperone binding assays.

Main Results:

• Two bridged arylamines (compounds 3 and 6) demonstrated potent and selective inhibition of norepinephrine (NE) uptake.
• This NE uptake inhibition was observed both in vitro and following in vivo administration.
• Pyridazine-containing compounds showed in vitro activity, but this was lost upon in vivo administration.
• None of the tested compounds interfered significantly with spiroperidol binding.

Conclusions:

• Bridged arylamines represent a promising class of selective norepinephrine reuptake inhibitors.
• Structural modifications, such as replacing the sulfur bridge, can yield compounds with significant in vivo efficacy.
• The pyridazine-containing analogs warrant further investigation despite loss of in vivo activity.