One‐Pot Sequential Synthesis of 2‐Amino‐4, 6‐Diaryl Pyrimidines Involving SO3H‐Functionalized Piperazinium‐Based Dicationic Ionic Liquids as Homogeneous Catalysts. Issue 30 (8th August 2019)

• Record Type: Journal Article
• Authors: Saikia, Susmita; Borah, Ruli
• Is Part Of: ChemistrySelect. Volume 4:Issue 30(2019)
• Page Start: 8751
• Page End: 8756
• Publication Date: 2019-08-08
• Subjects: Grinding -- Homogeneous -- Piperazinium dication -- Sulfonic group -- Substituted pyrimidines; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201902060
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: A new series of –SO3 H functionalized dicationic ionic liquids based on N, N, N′, N′ ‐ tetrasulfopiperazinium cation [TSPi] + and various anions [X] − (X=Cl, CF3 SO3, TsO) is synthesized and characterized by 1 H NMR, 13 C NMR, FTIR, elemental analysis and thermogravimetric studies. Brönsted acidity of these ionic liquids is determined by Hammett plot using UV‐Visible absorbance spectra. Further they are examined as acidic catalyst for one‐pot preparation of 2‐amino‐4, 6‐diaryl pyrimidines through Biginelli‐like reaction of acetophenone, aromatic aldehyde and urea followed by condensation‐aromatization reaction with phenylhydrazine under solvent‐free grinding method. The most acidic [TSPi][CF3 SO3 ]2 catalyst offers good to satisfactory yield within 15–25 min reaction time. Easy recyclability, simple and mild reaction conditions represent the advantages of this method. Abstract : The present work emphasizes on the one pot sequential synthesis of 5‐substituted 2‐amino‐4, 6‐diaryl pyrimidines catalyzed by a new series of three –SO3 H functionalized piperazinium based dicationic ionic liquids. This approach offers effective and easy methodology for this two step one‐pot reaction limiting the step of Biginelli product isolation. Room temperature grinding and recyclability of the catalyst are the key factors of this work.