Eco-Friendly Heterocyclic Synthesis Via Multicomponent Reactions Using Solid Base Catalysts: An Overview

Heterocyclic compounds, which contain at least one heteroatom (e.g., nitrogen, oxygen, sulfur) within their ring structures, are crucial in pharmaceuticals and agrochemicals due to their bioactive properties. They serve as the core components of numerous drugs, including antibiotics, anticancer agents, and agrochemicals like pesticides. Given the increasing demand for these compounds, the need for efficient and sustainable synthetic methods has become paramount. Multicomponent reactions (MCRs) have emerged as a powerful tool for the rapid and efficient synthesis of heterocyclic frameworks. By combining three or more reactants in a single step, MCRs offer high atom economy, reduced waste, and simplified reaction protocols. Solid base catalysts have been extensively utilized to improve the sustainability of these reactions further. These catalysts, including metal oxides and supported alkali metals, provide several advantages: enhanced selectivity, ease of recovery and reuse, and minimal environmental impact. This review explores the diverse MCR strategies for heterocyclic synthesis using solid base catalysts. It highlights their role in promoting green chemistry by enabling scalable and environmentally benign processes. Key examples, such as the synthesis of imidazoles, pyridines, pyrans, pyrimidine, etc, are discussed, demonstrating these methods' efficiency and industrial relevance. Solid base catalysis ensures operational simplicity and aligns with sustainable chemistry goals, making it a cornerstone in modern heterocyclic synthesis.