1,3-Disubstituted-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazines were prepared through the ring-closurereactions of the aminobenzylnaphthols with substituted aryl-andheteroarylaldehydes.

Spiro[benzo[h]quinoline-7,3′-indoline]diones and spiro[indoline-3,4′-pyrazolo[3,4-b]quinoline]diones were efficiently synthesized via one-pot multi-component reactions under ultrasound-promoted conditions. Spiro[benzo[h]quinoline-7,3′-indoline]dione derivatives were successfully developed by the reaction of isatins, naphthalene-1-amine and 1,3-dicarbonyl compounds. The spiro[indoline-3,4′-pyrazolo[3,4-b]quinoline]dione derivatives were prepared by the reaction of isatins, 5-amino-1-methyl-3-pheylpyrazole, and 1,3-dicarbonyl compounds by using ( ±)-camphor-10-sulfonic acid as a catalyst in H₂O/EtOH (3:1 v/v) solvent mixture. The antibacterial activity of the synthesized compounds was evaluated against,Enterococcus faecalis,Staphylococcus aureusandCandida albicans. Compounds 4b, 4h, and 6h showed the strongest antimicrobial activity toward both bacteria. The MIC values of these compounds ranged from 375–3000 µg/mL. The effect of these compounds (4b, 4h, 6h) as a function of applied dose and time was investigated by a kinetic study, and the interaction with these antimicrobial results was simulated by a molecular docking study. We also used the docking approach with Covid-19 since secondary bacterial infections. Docking showed that indoline-quinoline hybrid compounds 4b and 4h exerted the strongest docking binding value against the active sites of 6LU7. In addition, the synthesized compounds had a moderate to good free radical scavenging activity.

Since December 2019, humanity has faced an important global threat. Many studies have been published on the origin, structure, and mechanism of action of the SARS-CoV-2 virus and the treatment of its disease. The priority of scientists all over the world has been to direct their time to research this subject. In this review, we highlight chemical studies and therapeutic approaches to overcome COVID-19 with seven different sections. These sections are the structure and mechanism of action of SARS-CoV-2, immunotherapy and vaccine, computer-aided drug design, repurposing therapeutics for COVID-19, synthesis of new molecular structures against COVID-19, food safety/security and functional food components, and potential natural products against COVID-19. In this work, we aimed to screen all the newly synthesized compounds, repurposing chemicals covering antiviral, anti-inflammatory, antibacterial, antiparasitic, anticancer, antipsychotic, and antihistamine compounds against COVID-19. We also highlight computer-aided approaches to develop an anti-COVID-19 molecule. We explain that some phytochemicals and dietary supplements have been identified as antiviral bioproducts, which have almost been successfully tested against COVID-19. In addition, we present immunotherapy types, targets, immunotherapy and inflammation/mutations of the virus, immune response, and vaccine issues.

The Yb(OTf)3 catalyzed formal aza-Diels-Alder (or Povarov) reaction of cyclopentadiene and 1,3-cyclohexadiene with in situ-generated N-arylimines under conventional/ultrasonic techniques is herein described. This kind of three-component Povarov reaction results in quinoline and phenanthridine derivatives, which are important biological compounds.

New polycyclic-fused isoxazolo[4,5-e]pyridines and spirooxindoles were obtained via multicomponent reaction of 5-amino-3-methylisoxazole, indan-1,3-dione, and aromatic aldehydes and reaction of 5-amino-3-methylisoxazole, isatin, and β-diketones in the presence of (±)-camphor-10-sulfonic acid as an effective and nontoxic organocatalyst under ultrasound-promoted conditions. The antioxidant activity of the novel synthesized compounds was studied.

New fused pyrazolo[4,3-e]pyridines were obtained by multi-component reaction of 1,3-dimethyl-1H-pyrazol-5-amine or 3-phenyl-1H-pyrazol-5-amine, aromatic aldehydes and indan-1,3-dione in the presence of camphor-10-sulfonic acid (CSA) as an effective catalyst under ultrasound promoted conditions. The antioxidant activity of the pyrazolopyridine compounds 4b , 5c, 5e, 7a, 7b and 7c were determined.