Emerging Trends in Two- and Three-Component Efficient Synthetic Strategies for Functionalised and Fused Quinoxalines

Abstract

Quinoxalines are important moieties that mimic the naphthalene core unit, where two carbon atoms (C-1 and C-4) are replaced by N atoms. Many natural products and synthetic compounds contain functionalised and fused quinoxaline precursors having significant physicochemical properties and biological activities. Eventually these quinoxaline derivatives become significant building blocks in modern chemistry research. All these properties of quinoxaline encourage chemists to take up the challenges of discovering new methods for synthesizing functionalised and fused quinoxalines. Several methods were reported for synthesizing quinoxalines, like Ugi reactions, metal-catalysed multi-component reactions, microwave-assisted techniques, and neat reactions, including diversity-oriented synthesis. Since toxicity is related to metals and also influences the environment, scientists are trying to perform the most efficient organic synthesis in a greener approach by using environmentally benign solvents to afford atom economy, better yield of the products and keep the environment free from pollution. In this review, we are going to emphasize the recent advancement of two- and three- component efficient synthetic strategies of functionalised as well as fused quinoxaline derivatives. This review also outlines the schematic rationalization and the restriction of the synthetic methodologies that will enlighten the future prospects.