Vikas N. Telvekar

2-Amino-4H-chromene derivatives are noteworthy heterocyclic scaffolds known to have notable pharmacological potential, such as anticancer and antimicrobial effects. Traditional synthetic methods, however, are often limited to the use of toxic solvents, costly catalyst systems, and complicated work-up processes that lead to lower yields and environmental issues. Therefore, the synthesis of environmentally friendly protocols to enable their production, which are cost-effective, is an urgent goal in sustainable medicinal chemistry. We describe a novel, eco-friendly, one-pot, multicomponent reaction (MCR) procedure to the preparation of 2-amino-4H-chromene derivatives with tartaric acid as a commercially available biodegradable, non-toxic organocatalyst. The reaction is carried out through the condensation of aromatic aldehydes, dimedone, and malononitrile in ethanol at room temperature to make the conversion a rapid reaction under mild conditions. Excellent to moderate yields were achieved using tartaric acid as an acid catalyst at room temperature utilizing ethanol as a solvent. The advantages of the methodology included a reaction time of less than 30 minutes; reactions occurring under mild conditions and using low amounts of energy; a simple work-up procedure with minimal waste; low costs and high atom economy. The synthesis through tartaric acid offers a distinctive combination of advantages, including ease of use, good atom economy, energy cost-effectiveness, and the lack of toxic waste, and it is more efficient than traditional methods to overcome these limitations. This procedure is both environmentally friendly and scalable for the generation of biologically active amino-chromene scaffolds, aligning with the concepts of green chemistry.

In this study, we have developed an expeditious and efficient method for the synthesis of 2,4,5–triaryl imidazole derivatives using thiamine hydrochloride as a catalyst. The one-pot, solventfree- multicomponent reaction of an aromatic/heterocyclic aldehyde with benzyl and ammonium acetate at reflux conditions leads to the formation of title compounds in extremely good yields. This protocol offers several features, such as safe, simple, atom efficient, economical, mild conditions, minimum waste, easy work-up procedures, shorter reaction time (40-45 min), catalyst recyclability, etc. The developed methodology is operationally simple and eco-friendly.

An expeditious and highly efficient methodology for the synthesis of pyrazolopyranopyrimidine under aqueous conditions is reported using guanidine hydrochloride as a catalyst. One‐pot multicomponent synthesis from aryl/heterocyclic aldehyde, ethyl acetoacetate, barbituric acid, and hydrazine hydrate to give the final compound in moderate to excellent yield. The recyclability (up to 4 cycles), safe, low cost, and wide stability profile of guanidine hydrochloride fulfil the ideal properties of the catalyst. The current protocol shows several advantages such as its environmentally benign nature, shorter reaction time, high yield, simple work‐up procedure, broad substrate tolerance, absence of hazardous organic solvent, etc.

A forthright, effectual and more viable catalyst-free method has been developed for the synthesis of quinolone and pyrazole ring system in glycerol to achieve yields that were equivalent to or better than, those in conventional media. It is notable that the reaction was exclusively carried out in glycerol–acetic acid system, representing methodology is highly valuable from both environmental and economic points of view

An efficient and facile green method for synthesis of four substituted 1,5-benzodiazepine derivatives via a three-component reaction of dimedone, o-phenyl diamine, and various substituted aldehydes are designed using β-cyclodextrin as a catalyst at reflux condition. The current one-pot multicomponent methodology offers several advantages, such as good to excellent yields, simplicity in experimental procedure, easy work-up procedure, shorter reaction time, energy-conserving, broad substrate scope, avoidance of hazardous chemicals, etc. Further, the catalyst was recovered and recycled 4–5 times without compromising the yield of the final product. Graphical Abstract