A Secondary Amine Catalyzed Metal‐Free Multicomponent (One‐Pot) Synthesis of Biologically Active Aza‐Anthraquinone Derivatives, and Their Structure–Activity Relationship ( <scp>SAR</scp> ) Studies

ABSTRACT We report a metal‐free, green synthetic route to substituted Aza‐anthraquinones that was developed via a multicomponent reaction of aromatic aldehydes, active methylene substrates, and 2‐aminonaphthalene‐1,4‐dione, catalyzed by piperidine in ethanol at 70°C. This atom‐economical and regioselective protocol yielded functionalized Aza‐anthraquinone hybrids in high yields and Gram‐scale quantities, leveraging inexpensive starting materials and demonstrating broad scaffold compatibility. Biological evaluation revealed significant antifungal and antibacterial activities, with several compounds (4b, 4d,4e, 4f, 4g, 4l, and 4b) exhibiting superior inhibition zones compared to standard drugs (Gentamicin and Nystatin). Furthermore, molecular docking studies against the SARS‐CoV‐2 protein suggested compound 4a as a potential antiviral molecule, displaying a favorable glide score (−5.64 kcal/mol), glide energy (−41.27 kcal/mol), and high bioavailability (89.79%) compared to remdesivir.