Sustainable synthesis of imidazoles using a catalyst-free approach and ethyl lactate as a bio-based green solvent in the Debus-Japp-Radziszewski reaction

Abstract

A highly substituted family of imidazoles is effectively obtained through the Debus-Japp-Radziszewski reaction. In this process, benzil, ammonium acetate, and various benzaldehydes react in a particularly notable solvent: ethyl lactate (EL). This bio-based solvent, derived from biomass fermentation, stands out not only for its sustainable origin but also for its remarkable properties. Ethyl lactate is biodegradable, health-risk-free, is easily recyclable, and is non-corrosive, categorizing it as an exemplary green solvent. The multicomponent reaction, carried out under these conditions, eliminates the need for a catalyst, resulting in products with good yields. The isolation of the products is very simple, requiring only filtration, as they are insoluble in the solvent. In this way, this methodology aligns with various principles of green chemistry, emphasizing the strategic choice of ethyl lactate. This choice has a positive impact on the synthesis of imidazoles, well-known for their pharmacological properties.

Graphical Abstract

Keywords:

• Multicomponent reactions
• heterocycles
• aldehydes
• ketones
• green chemistry

Acknowledgments

The authors are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support, Conselho Nacional de Desenvolvimento Tecnológico (CNPq) for scholarships granted to P.N.A. and Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) for a fellowship to J.A.H.M.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ).