Eco-friendly Approaches to Chromene Derivatives: A Comprehensive Review of Green Synthesis Strategies.

Synthetic routes of chromene are an area of thrust research due to its wide application as pigments, agrochemicals, cosmetics, and an important nucleus scaffold for various pharmaco-logically active drugs. The chromene nucleus is an important moiety for the discovery of new drug candidates owing to its broad range of pharmacological actions like antitumor, anti-inflammatory, antiviral, and many others. However, traditional synthesis techniques frequently use unsafe reagents and produce hazardous waste, presenting environmental issues. The eco-friendly production of chromene derivatives utilizes sustainable raw materials, non-toxic cata-lysts, and gentle reaction conditions to reduce ecological consequences. Innovative methods like microwave irradiation, ultrasound synthesis, the use of environmentally friendly solvents, a cata-lyst-based approach with minimal environmental impact, and mechanochemistry-mediated syn-thesis are implemented. These approaches provide benefits in scalability, cost-effectiveness, and ease of purification. This review compiles and presents various recently reported green synthetic strategies of chromene and its derivatives and gives the reader a clear idea of the detailed and crit-ical aspects of various synthetic protocols described.