Multisite-Sequential Cyclization To Construct 1,2,4-Triazole-Based N-Fused Heterocyclics.

Area of Science:

• Organic Chemistry
• Heterocyclic Chemistry
• Synthetic Chemistry

Background:

• Traditional synthesis of N-fused heterocycles often involves multiple steps, limited substrate scope, and the use of hazardous reagents.
• There is a need for more efficient, safer, and versatile methods for constructing complex heterocyclic scaffolds.

Purpose of the Study:

• To develop a feasible and efficient protocol for synthesizing N-fused 1,2,4-triazoles, benzothiazides, benzoselenazinones, and quinazolinones.
• To overcome limitations of existing synthetic methods, including lengthy procedures, narrow substrate scope, and toxicity concerns.

Main Methods:

• Utilized atomic groups (potassium thiocyanate (KSCN), potassium selenocyanate (KSeCN), and cyanamide (NH2CN)) as key reaction factors.
• Employed *o*-bromobenzoyl hydrazides and formyls as core components in the synthesis.
• Developed a one-pot or streamlined reaction sequence.

Main Results:

• Successfully synthesized a range of N-fused 1,2,4-triazole derivatives fused with benzothiazides, benzoselenazinones, and quinazolinones.
• The proposed method is significantly shorter and more versatile than previous multi-step approaches.
• The synthesis avoids the use or generation of hazardous substances, presenting a safer alternative.
• The synthesized fused-heterocyclic selenium and quinazolinone derivatives exhibited promising fluorescent properties.

Conclusions:

• The developed protocol offers a practical, efficient, and environmentally friendlier approach to synthesizing complex N-fused heterocyclic compounds.
• The methodology enables access to novel benzoselenazinone and quinazolinone derivatives with potential applications in materials science, evidenced by their fluorescence.
• This work provides a valuable tool for medicinal chemistry and materials research.