# Microwave-assisted synthesis of 2’-hydroxychalcone derivatives in 1-decyl-3-methylimidazolium bromide ionic liquid and its computational study

## TL;DR

This paper describes a microwave-based method to synthesize chalcone derivatives in an ionic liquid, supported by computational analysis of reactivity and reaction mechanisms.

## Contribution

The study combines microwave-assisted synthesis with computational reactivity analysis to optimize chalcone production in an ionic liquid.

## Key findings

- Microwave-assisted synthesis in [DMIm]Br yielded chalcone derivatives with 65-81% efficiency.
- Fukui function analysis predicted reactivity trends matching experimental yields: o-vanillin > anisaldehyde > salicylaldehyde.
- Cyclization of 2,2’-dihydroxy-3-methoxychalcone occurs in two steps, with the first step being rate-determining.

## Abstract

Three 2’-hydroxychalcone derivatives were synthesized via microwave-assisted organic synthesis using the ionic liquid 1-decyl-3-methylimidazolium bromide ([DMIm]Br) as the medium. The reactions, conducted at 80°C under 300 W microwave power for 10 min, yielded products with yields of 65, 72 and 81%. A computational study using density functional theory with B3LYP and ωB97X functionals examined the reactivity of precursors via Fukui function analysis. Results showed that higher reactivity of benzaldehyde derivatives correlated with increased product yields: o-vanillin > anisaldehyde > salicylaldehyde. The cyclization of 2,2’-dihydroxy-3-methoxychalcone to its flavanone derivative was also simulated, revealing a two-step mechanism with the first step being rate-determining (activation energy: 63.8 kJ mol−1). Additionally, the formation of [DMIm]Br was found to proceed through an SN2 mechanism, with an activation energy of 197.3  kJ mol−1. These experimental and computational findings underscore the predictive power of Fukui-based reactivity in optimizing chalcone synthesis in ionic liquid media.