Synthesis of two nitrogen-containing polyaromatic compounds through gold catalysis/DBU-promoted cyclizations

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Heterocyclic Chemistry

Background:

• Quinazoline derivatives are important scaffolds in medicinal chemistry.
• Efficient synthesis of complex heterocyclic systems remains a challenge.
• Indole and nitrile functionalities offer versatile reaction sites.

Purpose of the Study:

• To report an efficient synthetic route for novel benzo[7,8]indolizino[2,3,4,5-ija]quinazoline derivatives.
• To explore a new cyclization strategy involving indole, nitrile, and aldehyde groups.
• To provide access to a unique class of fused heterocyclic compounds.

Main Methods:

• The synthesis involves the reaction between 2-(2-ethynylaryl)acetonitriles and anthranils.
• A key step is the formation of 7-formylindole intermediates.
• 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) is used to activate a novel indole-nitrile-aldehyde cyclization.

Main Results:

• Efficient synthesis of target benzo[7,8]indolizino[2,3,4,5-ija]quinazoline derivatives was achieved.
• The developed method provides a novel cyclization pathway.
• The reaction proceeds through 7-formylindole intermediates.

Conclusions:

• A new and efficient synthetic strategy for benzo[7,8]indolizino[2,3,4,5-ija]quinazoline derivatives has been established.
• The methodology offers a valuable tool for constructing complex fused heterocyclic systems.
• This work expands the synthetic accessibility of novel quinazoline-based compounds.