Catalyst-Free, Glycerol-Assisted Facile Approach to Imidazole-Fused Nitrogen-Bridgehead Heterocycles

Phenanthridine derivatives as promising new anticancer agents: synthesis, biological evaluation and binding studies

Aim: Phenanthridines are an essential class of nitrogenous heterocycles with extensive applications in medicinal chemistry. The development of efficient and eco-friendly methods for the preparation of chirally pure dihydropyrrolo[1,2-f]phenanthridines (5a-h), and their in vitro evaluation and modeling studies as potential anticancer, antioxidant and DNA cleavage agents is reported. Methodology & results: Compounds 5a-h were prepared through a facile one-pot synthesis and characterized by infrared, high resolution mass spectrometry, ¹H and ¹³C nuclear magnetic resonance. The molecules were subjected to virtual screening and docking analysis against selected human molecular targets. Compound 5g displayed good binding properties as well as significant anticancer and DNA cleavage activity. Conclusion: Compound 5g has been identified as a potential lead candidate for further testing against additional cancer cell lines and animal models in future.

Mekheimer R, M. Hayallah A, A. Abo Elsoud F, U. Sadek K. Recent Advances in the Utility of Glycerol as a Benign and Biodegradable Medium in Heterocyclic Synthesis

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Glycerol is a non-toxic, recyclable and biodegradable organic waste produced as a byproduct in the production of biodiesel fuel. Currently, glycerol is considered a green solvent and catalyst for a large variety of applications. This work discusses the significance of glycerol for heterocyclic synthesis. All the reported studies consider glycerol as an efficient and sustainable benign medium.

Facile synthesis of 3-substituted imidazo[1,2-a]pyridines through formimidamide chemistry

A facile entry to 3-aryl/alkenyl/alkynyl substituted imidazo[1,2-a]pyridines (3a–p, 6a–d & 9a–9e) has been developed from readily available benzyl/allyl/propargyl halides and 2-amino pyridines as substrates via formimidamide chemistry that is devoid of caustic or expensive reagents, such as transition metal complexes. Quantum chemical calculations performed to understand the underlying mechanism of the transformation revealed a preference for intramolecular Mannich-type addition over pericyclic 1,5-electrocyclization for the systems reported herein that enable a Baldwin allowed 5-exo-trig cyclization instead of a formally anti-Baldwin 5-endo-trig process.

A facile entry to 3-substituted imidazo[1,2-a]pyridines from halides and 2-amino pyridines via formimidamide chemistry has been developed through a formal anti-Baldwin 5-endo-trig cyclization that becomes a thermally allowed 5-exo-trig cyclization.

A practical green approach to diversified spirochromene/spiropyran scaffolds via a glucose–water synergy driven organocatalytic system

Development of a versatile, new glucose–water organocatalytic system promoted, one pot, practical green method for the synthesis of diversified spirochromenes/spiropyrans is reported.