# Aqueous glyoxal: a versatile synthon in heterocyclic synthesis

## TL;DR

This review explores how aqueous glyoxal can be used to create a wide variety of complex organic molecules, especially heterocycles, through different chemical strategies.

## Contribution

The paper provides a comprehensive overview of aqueous glyoxal's role in synthesizing diverse molecular frameworks using one-pot and multicomponent methods.

## Key findings

- Aqueous glyoxal can form five- and six-membered heterocycles through addition and condensation reactions.
- It is effective in creating aromatic compounds, fused heterocycles, and polycyclic systems using various catalysts.
- The review highlights one-pot and multicomponent reaction strategies for efficient synthesis.

## Abstract

Glyoxal is a versatile, non-volatile compound with a wide range of applications, attracting significant interest from both researchers and various industries. It can be synthesized by numerous methods and is potentially derivable from natural sources. Moreover, glyoxal forms various hydrates and oligomers (e.g., dimers and trimers). Its high reactivity allows it to undergo addition, condensation, and crosslinking reactions with a wide range of compounds, including alcohols, amines, aldehydes, carboxylic acids, cellulose, polyvinyl alcohol, and urea. This review discusses the applications of aqueous glyoxal as a versatile reagent in organic synthesis, with a focus on protocols for generating diverse molecular frameworks, including five- and six-membered heterocycles, aromatic compounds, fused heterocycles, polyaza polycyclic compounds, polyoxa polycyclic compounds and polyaza–polyoxa polycyclic compounds. The employed strategies include one-pot, multicomponent reactions and sequential methods, which use different catalysts under various conditions.

This review highlights the applications of aqueous glyoxal as a versatile reagent in organic synthesis, with a focus on protocols for generating diverse molecular frameworks, including five- and six-membered heterocycles.