Ionic liquid‐assisted synthesis of 2‐amino‐3‐cyano‐4H‐chromenes: A sustainable overview

Abstract

In advanced research, the role of ionic liquid is gradually enhanced as an alternative finding. For a long time, many strategies have been developed based on the ionic liquid conveying the role of greener solvents or catalysts. In the case of multi‐component synthesis, ionic liquids have a wide range of applications to revise a method in a sustainable and greener approach. The last two decades have given a number of methods to achieve the 4H‐chromene derivatives by applying different types of ionic liquids. Especially, 2‐amino‐3‐cyano‐4H‐chromene moiety that exhibits pharmacological and biological activity, have been synthesized using simple or functionalized ionic liquids such as basic, acidic, neural, metal‐tagged, or carbon‐oriented ionic liquid. In this review, we have concised the multicomponent reactions that have been reported to synthesize the 4H‐chromene derivatives following the versatility of ionic liquids.

Design, synthesis, theoretical study, antioxidant, and anticholinesterase activities of new pyrazolo-fused phenanthrolines

“…38 Structurally, these final compounds have a 2-amino-3-cyanoquinoline system that is of great interest for both reactivity and biological applications. Analogues to this system have been obtained through ionic liquid assisted synthesis, 40 which may be used as an alternative synthetic strategy in future works.…”

Construction of a Dual-Functionalized Acid–Base Nanocatalyst via HEPES Buffer Functionalized on Fe3O4 as a Reusable Catalyst for Annulation Reactions

“…Moreover, it can be converted to interesting heterocyclic compounds, especially in drug research . Among these, 2-amino-3-cyano-4 H -chromenes and pyrano­[2,3- c ]­pyrazoles have gained significant attention due to their promising biological properties. − Due to their unique chemical structure and reactivity, these compounds are attractive targets for drug discovery and development. , In addition, several approaches for synthesizing these compounds have been documented, such as the use of homogeneous catalysts. ,,− Current methods for synthesizing these compounds often have limitations, such as elevated temperature, extended reaction times, insufficient product yields, harsh conditions, difficulty in obtaining materials, and complicated postreaction steps. Thus, herein, an efficient protocol is proposed for the synthesis of these fused heterocycles in excellent yields by using a novel heterogeneous method.…”

Advancements in the Preparation of 4H‐Chromenes: An Overview

“…Generally, these established methods can be classified into three categories, namely the nucleophilic functionalization of 2 H ‐chromene derivatives like 1‐benzopyrylium ion or 2‐iminochromene, the 4 H ‐chromene ring formation involved cycloaddition or cyclization reactions, and miscellaneous reactions. Although base‐catalyzed tandem reactions of salicylaldehydes or salicyclic imines with α,β‐unsaturated compounds, [3] and enantioselective organocatalyzed, [4a] ionic liquid‐assisted [4b] and recently published MCRs (multicomponent reactions) based on aldehydes [4c] for the synthesis of 2‐amino‐4 H ‐chromenes have been published to introduce protocols for the synthesis of 4 H ‐chromenes, these reviews covered only small parts based on transformations on salicylaldehydes or salicyclic imines. In addition, some recently developed catalytic asymmetric methods are rarely included.…”