Ultrasound-assisted aqua-mediated synthesis of multi-substituted tetrahydropyridine-3-carboxylates using N-carboxymethyl-3-pyridinium hydrogensulfate ([N-CH2CO2H-3-pic]+H SO4-) as a new efficient ionic liquid catalyst

A simple, straightforward, and ultrasound-promoted method for the preparation of some highly functionalized tetrahydropyridines reported via pseudo five- component reaction of (hetero)aromatic aldehydes, different anilines, and alkyl acetoacetates in the presence of [N-CH2CO2H-(-)(3) pic](+) HSO4-, as a novel ionic liquid, in green aqueous medium. The IL was synthesized utilizing simple and easily-handled substrates and characterized by FT-IR, H-1 NMR, C-13 NMR, GC-MASS, FESEM, EDX, and TGA/DTG techniques. The procedure contains some highlighted aspects which are: (a) performing the MCR in the presence of aqua and sonic waves, as two main important and environmentally benign indexes in green and economic chemistry, (b) high yields of products within short reaction times, (c) convenient work-up procedure, (d) preparing the new IL via simple substrates and procedure.

Automated summary

A simple and straightforward method was developed for the preparation of highly functionalized tetrahydropyridines via a pseudo five-component reaction, utilizing a novel ionic liquid in a green aqueous medium. The new ionic liquid was synthesized from easily-handled substrates and characterized by various techniques, showing efficient and convenient preparation of products with high yields in short reaction times.