Molecular recognition studies on naphthyridine derivatives

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Chemical Biology

Background:

• Designing host molecules with enhanced hydrogen bonding and preorganization is crucial for molecular recognition.
• Biotin and its analogues are important targets in biological and chemical systems.
• Understanding binding affinities is key to developing selective receptors.

Purpose of the Study:

• To synthesize and characterize three host molecules (I-III) with improved hydrogen bonding and conformational preorganization.
• To investigate the binding interactions between these hosts and biotin analogues (1-5).
• To quantify the binding constants (Kb) and elucidate the contributions of different interactions.

Main Methods:

• Synthesis of host molecules I-III and biotin analogues 1-5.
• 1H-NMR titration experiments were conducted under varying concentration conditions.
• Statistical analysis using a presence-absence matrix was applied to determine interaction contributions.

Main Results:

• Association constants (Kb) were determined for the interactions between hosts I-III and biotin analogues 1-5.
• Naphthyridine derivatives II and III demonstrated potent binding affinities.
• Complex stabilization was attributed to synergistic hydrogen bond interactions.

Conclusions:

• Naphthyridine-based hosts II and III are effective receptors for (+)-biotin methyl ester.
• Enhanced hydrogen bonding donor strength and conformational preorganization significantly contribute to binding affinity.
• The study provides insights into the design principles for selective molecular recognition systems.