Regioselective Reactions, Spectroscopic Characterization, and Cytotoxic Evaluation of Spiro-pyrrolidine Thiophene

Small Molecules with Spiro-Conjugated Cycles: Advances in Synthesis and Applications

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Antioxidant activity of novel nitrogen scaffold with docking investigation and correlation of DFT stimulation

Heterocyclic scaffolds are frequently employed in drug development to treat a variety of conditions, including cancers. These substances have the ability to engage covalently or non-covalently with particular residues in the target proteins, inhibiting them. In this study, the formation of N-, S-, and O-containing heterocycles by the interaction of chalcone with nitrogen-containing nucleophiles such as hydrazine, hydroxyl amine, guanidine, urea, and aminothiourea was explored. FT-IR, UV-visible, NMR, and mass spectrometric studies were used to confirm the heterocyclic compounds that were produced. These substances were tested for their antioxidant activity by their capacity to scavenge the artificial radicals 2,2-diphenyl-1-picrylhydrazyl (DPPH). The strongest antioxidant activity was demonstrated by compound 3 (IC50 = 93.4 μM), whereas compound 8 (IC50 = 448.70 μM) had the lowest activity when compared to vitamin C (IC50 141.9 μM). Also, the experimental findings and the docking estimation of these heterocyclic compounds with PDBID:3RP8 were in agreement. Additionally, the compounds' global reactivity characteristics, such as HOMO-LUMO gaps, electronic hardness, chemical potential, electrophilicity index, and Mulliken charges, were identified using DFT/B3LYP/6-31G(d,p) basis sets. The two chemicals that displayed the best antioxidant activity also had their molecular electrostatic potential (MEP) ascertained using DFT simulations.

Synthesis, antimicrobial activity and molecular docking studies of spiroquinoline-indoline-dione and spiropyrazolo-indoline-dione derivatives

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 aureus and Candida 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.

Design, Synthesis, and Bioactivity of Spiro Derivatives Containing a Pyridine Moiety

We designed and synthesized a series of pyridine spiro derivatives and evaluated their insecticidal and antiviral activities. Some compounds exhibited good insecticidal and antiviral activities. Notably, the E series of compounds displayed good insecticidal activity against Tetranychus urticae. Compounds E20 (EC₅₀ = 63.68 mg/L) and F4 (EC₅₀ = 47.81 mg/L) exhibited inactivation activities against the tobacco mosaic virus (TMV), which were similar to that of Ningnanmycin (EC₅₀ = 58.01 mg/L). Molecular docking showed that compounds E20 and F4 exhibited satisfactory affinities for the TMV coat protein (TMV-CP), with binding energies (-6.7 and -6.4 kcal/mol, respectively) slightly lower than that of Ningnanmycin (-6.3 kcal/mol). Further, molecular dynamics analysis revealed that compounds E20 and F4 exhibited better binding stability values than Ningnanmycin. Microscale thermophoresis showed that compounds E20 (K_d = 0.053 ± 0.016 μM) and F4 (K_d = 0.045 ± 0.022 μM) bound more strongly to TMV-CP than Ningnanmycin (K_d = 0.10 ± 0.029 μM). The results of transmission electron microscopy showed that these two compounds hindered the self-assembly and growth of TMV. In summary, we showed that these pyridine spiro derivatives could be used as a basis for the research and development of novel pesticides.

Engaging Isatins in Multicomponent Reactions (MCRs) - Easy Access to Structural Diversity

Multicomponent reactions (MCRs) are a valuable tool in diversity-oriented synthesis. Its application to privileged structures is gaining relevance in the fields of organic and medicinal chemistry. Isatin, due to its unique reactivity, can undergo different MCRs, affording multiple interesting scaffolds, namely oxindole-derivatives (including spirooxindoles, bis-oxindoles and 3,3-disubstituted oxindoles) and even, under certain conditions, ring-opening reactions occur that leads to other heterocyclic compounds. Over the past few years, new methodologies have been described for the application of this important and easily available starting material in MCRs. In this review, we explore these novelties, displaying them according to the structure of the final products obtained.

Anticancer potential of spirocompounds in medicinal chemistry: A pentennial expedition

Spirocompounds constitute an important class of organic frameworks enveloping numerous pharmacological activities, among them, the promising anticancer potential of spirocompounds have enthused medicinal chemists to explore new spiro derivatives with significantly improved pharmacodynamic and pharmacokinetic profile along with their mechanism of action. The current review intends to provide a sketch of the anticancer activity of various spirocompounds like spirooxindole, spiroisoxazole, spiroindole etc, from the past five years unfolding various aspects of pharmacological activities and their structure-activity relationships (SARs). This literature analysis may provide future direction for the efficient design of novel spiromolecules with enhanced safety and efficacy.

The application of isatin-based multicomponent-reactions in the quest for new bioactive and druglike molecules

Oxindole derivatives are known for their great interest in the field of Medicinal Chemistry, as they display vast biological activities. Recent efforts concerning the preparation of oxindole derivatives using isatin-based multicomponent reactions (MCRs) constitute a great advance in generating druglike libraries fast and with wide scaffold diversity. In this review, we address those recent developments, exploring the synthetic pathways and biological activities described for these compounds, namely antitumor, antibacterial, antifungal, antiparasitic, antiviral, antioxidant, anti-inflammatory and central nervous system (CNS) pathologies. To add new depth to this work, we used a well-established web-based free tool (SwissADME) to evaluate the most promising scaffolds in what concerns their druglike properties, namely by evaluating their compliance with some of the most valuable rules applied by medicinal chemists in both academia and industrial settings (Lipinski, Ghose, Veber, Egan, Muegge). The aim of this review is to endorse isatin-based MCRs as a valuable synthetic approach to attain new hit compounds bearing the oxindole privileged structure, while critically exploring these scaffolds' druglike properties.