The conformational flexibility of aromatic retinoids

Area of Science:

• Computational chemistry
• Molecular modeling
• Medicinal chemistry

Background:

• Arotinoids, including (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl] benzoic acid (TTNPB), are potent agents in cancer prevention and therapy.
• Understanding the conformational flexibility of these molecules is crucial for optimizing their therapeutic potential.

Purpose of the Study:

• To investigate the conformational landscape of TTNPB and its derivatives using computational methods.
• To characterize the rotational flexibility and energy barriers of key molecular fragments.

Main Methods:

• Geometry optimizations were performed using AM1 and PM3 computational methods.
• Analysis of 19 arotinoid structures, focusing on 16 TTNPB conformations and 14 derivatives.
• Evaluation of rotational barriers for tetralenyl and benzoic acid moieties.

Main Results:

• Substantial non-planarity was observed between the aromatic moieties of the studied arotinoids.
• High rotational flexibility was predicted for arotinoid ring fragments.
• Low energy barriers were found for tetralenyl ring rotation, and varying barriers for benzoic acid moiety rotation depending on the computational method.

Conclusions:

• Arotinoids exhibit significant conformational flexibility, particularly in their ring fragments.
• This flexibility may play a key role in the ability of arotinoids to bind effectively to receptor sites.
• Computational insights can guide the design of novel arotinoid-based therapeutics.