Alternative Route Toward Nitrones: Experimental and Theoretical Findings

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Computational Chemistry

Background:

• Nitrones are crucial heterocyclic compounds with significant applications in synthesizing biologically active molecules and as therapeutic agents.
• Their utility as spin-trap reagents and versatile synthetic intermediates drives ongoing research interest.
• Understanding nitrone formation and isomerization is key to developing novel synthetic strategies.

Purpose of the Study:

• To investigate the condensation reactions of hydrazonophenylacetaldehyde oxime with various aldehydes and ketones.
• To elucidate the formation of 3,4-dihydro-1,2,4-triazine-based nitrones and their open-chain isomers.
• To computationally validate the experimental observations regarding nitrone formation and equilibrium.

Main Methods:

• Synthesis of hydrazonophenylacetaldehyde oxime from 2-isonitrosoacetophenone.
• Condensation reactions with salicylaldehyde, p-tolualdehyde, and acetone.
• Characterization of reaction products using spectroscopic techniques and computational methods (DFT and ab initio molecular dynamics).

Main Results:

• The reaction of hydrazonophenylacetaldehyde oxime with salicylaldehyde yielded exclusively the open-chain isomer.
• Reactions with p-tolualdehyde and acetone produced nitrones that exist in equilibrium with their open-chain isomers.
• Computational simulations supported the experimental findings on the formation and stability of these nitrone derivatives.

Conclusions:

• The study successfully demonstrated new synthetic routes to various nitrone derivatives.
• The research highlights the importance of reaction conditions in controlling the formation of cyclic nitrones versus open-chain isomers.
• Computational chemistry provides a powerful tool for understanding and predicting the behavior of these heterocyclic compounds.