Synlett 2024; 35(14): 1648-1668
DOI: 10.1055/a-2201-7705
account

The Synthesis of Nitrogen- and Oxygen-Containing Heterocyclic Scaffolds Assisted by Ionic Liquids: A 2022 Literature Survey

a   L. M. College of Pharmacy, Navrangpura, Ahmedabad 380009, Gujarat, India
,
Neha R. Raghani
a   L. M. College of Pharmacy, Navrangpura, Ahmedabad 380009, Gujarat, India
,
Meet S. Desai
b   o2h Discovery Pvt. Ltd., Panchratna Industrial Estate, Changodar, Ahmedabad 382213, Gujarat, India
,
Shraddhaba J. Chudasma
c   Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Marwadi University, Rajkot-Morbi Highway, Rajkot 360 003, Gujarat, India
,
Kumkum D. Virani
a   L. M. College of Pharmacy, Navrangpura, Ahmedabad 380009, Gujarat, India
› Author Affiliations


Abstract

Heterocycles have gained recognition as vital components in approved drugs, drawing substantial attention from the scientific community. Ionic liquids (ILs) have been utilized for their transformative roles in heterocycle synthesis, showcasing distinctive properties that are pivotal in diverse chemical transformations, while also acting as effective catalysts and offering safer alternatives to volatile organic solvents. This account delves into the synthesis of nitrogen- and oxygen-containing heterocyclic structures, employing various ILs such as ammonium, cholinium, DABCO-based, DBU-based, guanidinium-based, imidazolium, phosphonium, pyridinium, and other miscellaneous examples. They have proven indispensable in facilitating reactions like the Fischer indole synthesis, the Biginelli reaction, Knoevenagel condensations and many more. Notably, the recyclability of ILs serves as a valuable asset, aiding in the completion of intricate synthetic pathways, multicomponent reactions, and one-pot syntheses, ultimately enhancing yields. This account, covering the literature published in 2022, seeks to guide researchers in selecting suitable ILs for specific chemical reactions that enable the synthesis of aza- and/or oxa-heterocycles. The described advancements represent promising prospects for drug development and other applications within the domain of heterocyclic chemistry.

1 Introduction

2 Construction of Heterocycles Catalyzed by Ionic Liquids

2.1 Ammonium Ionic Liquids

2.2 Cholinium-Based Ionic Liquids

2.3 DABCO-Based Ionic Liquids

2.4 DBU-Based Ionic Liquids

2.5 Guanidinium-Based Ionic Liquids

2.6 Imidazolium Ionic Liquids

2.7 Phosphonium Ionic Liquids

2.8 Pyridinium Ionic Liquids

2.9 Other Ionic Liquids

3 Summary and Outlook

4 Abbreviations



Publication History

Received: 05 October 2023

Accepted after revision: 30 October 2023

Accepted Manuscript online:
30 October 2023

Article published online:
20 December 2023

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