Solvent-Free Condensation of Methyl Pyridinium and Quinolinium Salts with Aldehydes Catalyzed by DBU

Abstract

Methylpyridinium and methylquinolinium salts were condensed under solvent-free conditions with aromatic aldehydes in the presence of 1,8-diazabicyclo[5.4.]undec-7-ene (DBU) as catalyst, by grinding at room temperature. The products are dyes or useful intermediates. The DBU can be easily recycled and reused.

GRAPHICAL ABSTRACT

Keywords:

• Green chemistry
• Knoevenagel condensation
• styryl dyes

ACKNOWLEDGMENTS

We gratefully acknowledge the CNRS (National Center for Scientific Research), the “Region Basse-Normandie,” the University of Boumerdes (Algeria), the Franco-Algerian program for the Superior Education (PROFS), and the Algerian-French cooperation for a BAF grant for L. Loucif Seiad. Also the authors thank Rémy Legay and Baptiste Rigaud for NMR spectra and Mrs. Karine Jarsalé for ESIMS and HRMS analysis.

Notes

^a λ _max (nm), ϵ (L mol⁻¹ cm⁻¹).