Inherent Flexibility vis‐à‐vis Structural Rigidity in Chemically Stable Antimalarial Dispiro N‐Sulfonylpiperidine Tetraoxanes

Abstract

Structurally diverse and chemically stable tetraoxanes were formed by peroxidation of N-sulfonylpiperidones. X-ray analysis revealed that the crystal structures possess central spiro-2,5disubstituted tetraoxane rings trans fused to 6-membered piperidine and cyclohexylidene substituents in classical chair conformations. The more flexible cycloheptane ring exhibited pseudorotation between chair and twist chair conformation.The two sulfonyl oxygen atoms act as hydrogen-bonding acceptors and participate in hydrogen bonding. Docking calculations showed that the tetraoxanes are aligned parallel to the plane of the porphyrin ring of heme so that the iron can attack the OÀO bond to initiate redox-mediated reaction to render nanomolar antimalarial potency to these compounds against P. falciparum 3D7.[a] Dr.

Green and Mechanochemical One-Pot Multicomponent Synthesis of Bioactive 2-amino-4H-benzo[b]pyrans via Highly Efficient Amine-Functionalized SiO2@Fe3O4 Nanoparticles

“…In the last few years, tetrahydrobenzo­[ b ]­pyrans and its analogues have attracted great attention as they are part and parcel of various heterocyclic natural products and drugs that exhibit anticoagulant, antitumor, anticancer, antiallergic, diuretic, and antibacterial properties. − Additionally, they exhibit a broad spectrum of applications as cognitive enhancers that are used for treating neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, acquired immune deficiency syndrome (AIDS), and Down’s syndrome. , 4 H -benzo­[ b ]­pyran or chromene scaffold is found in several drugs that are pharmacologically active, for example, 2,7,8-triamino-4-(3-bromo-4,5-dimethoxyphenyl)-4 H -chromene-3-carbonitrile (A), 2-amino-4-(3-bromo-4,5-dimethoxyphenyl)-4 H -chromene-3-carbonitrile (B), ethyl-2-(2-amino-6-bromo-3-cyano-4 H -chromene-4-yl)-2-cyanoacetate (C), 2-amino-7-(dimethylamino)-4-(4-(dimethylamino)­naphthalene-1-yl)-4 H -chromene-3-carbonitrile (D), 2-amino-4-(furan-3-yl)-6,6-dimethyl-5-oxo-5,6,7,8-tetrahydro-4 H -chromene-3-carbonitrile (E), and 2-amino-6,6-dimethyl-5-oxo-4-(thiophen-3-yl)-5,6,7,8-tetrahydro-4 H -chromene-3-carbonitrile (F) shown in Figure . Because of the versatile utilization of substituted pyran analogues in medicinal chemistry, there is an upsurge to develop simple, inexpensive, and high yielding methods for their synthesis. , Our research group is focused on the design and synthesis of newer antimalarial drugs, single-crystal structure analysis, and catalysis of small molecules. − In continuation to this search, we had synthesized new and efficient economically benign catalyst NH 2 @SiO 2 @Fe 3 O 4 to optimize its efficacy in the synthesis of tetrahydrobenzo­[ b ]­pyrans. Adopting the fascinating advantages of MCRs, herein, we wish to report a library of 2-amino-4 H -benzopyran derivatives via condensation of the three-component (aromatic aldehyde, malononitrile, and dimedone) one-pot reaction catalyzed by amine-functionalized silica magnetic nanoparticles (ASMNPs).…”

Interaction of coumarin triazole analogs to serum albumins: Spectroscopic analysis and molecular docking studies

“…Our research group has been working on a diversified area including design and synthesis of newer antimalarial compounds, single crystal structure analysis, and interaction study of small molecules with serum albumins . To further rationalize the interaction of newly developed antimalarial drug candidate, we selected four most active compounds, viz., CUM 1‐4 (Figure ) with antimalarial activities, IC 50 values; 0.763, 0.893, 1.496, and 1.817 μg/mL against Plasmodium falciparum .…”