Application of a novel deep eutectic solvent as a capable and new catalyst for the synthesis of tetrahydropyridines and 1,3-thiazolidin-4-ones

Hadis Goudarzi; Davood Habibi; Arezo Monem

doi:10.1038/s41598-023-32882-0

Application of a novel deep eutectic solvent as a capable and new catalyst for the synthesis of tetrahydropyridines and 1,3-thiazolidin-4-ones

Sci Rep. 2023 Apr 10;13(1):5804. doi: 10.1038/s41598-023-32882-0.

Authors

Hadis Goudarzi¹, Davood Habibi², Arezo Monem¹

Affiliations

¹ Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran.
² Department of Organic Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran. davood.habibi@gmail.com.

Abstract

A novel deep eutectic solvent (ETPP-Br/THF-TCA-DES) was prepared by a mixture of ethyl triphenylphosphonium bromide (ETPP-Br) and tetrahydrofuran-2,3,4,5-tetra-carboxylic acid (THF-TCA, mole ratio 7:3), characterized by FT-IR, TGA/DTA, densitometer, eutectic point, and ¹H NMR techniques and used as a capable and new catalyst for the synthesis of two sets of compounds: (1) the four new [a(1-4)] and the eleven [a(5-15)] known alkyl 1,2,6-trisubstituted-4-[(hetero)arylamino]-1,2,5,6-tetrahydropyridine-3-carboxylates and (2) the two new [b(1-2)] and the eight [b(3-10)] known 1,3-thiazolidin-4-ones in DES with short reaction time, high yields, and easy recycling and separation of the DES catalyst. There is a nice consistency between the proposed structure of the DES compound, the integration values of the ¹H NMR peaks and the ratio of ETPP-Br to THF-TCA obtained from the eutectic point phase diagram. Also, the decrease in splitting patterns of the peaks in DES, compared to the two starting materials can be the good evidence of the hydrogen bond formation between the two components.