Synthesis, Biological Evaluation and Molecular Docking Studies of Piperidinylpiperidines and Spirochromanones Possessing Quinoline Moieties as Acetyl-CoA Carboxylase Inhibitors

Sulfonamide based pyrimidine derivatives combating Plasmodium parasite by inhibiting falcipains-2 and falcipains-3 as antimalarial agents

In this report, we present the design and synthesis of a novel series of pyrimidine-tethered spirochromane-based sulfonamide derivatives aimed at combating drug resistance in malaria. The antimalarial effectiveness of these compounds was assessed in vitro. Structural validation of the synthesized compounds was conducted using mass spectrometry and NMR spectroscopy. Strong antimalarial activity against CQ-sensitive (3D7) and CQ-resistant (W2) strains of Plasmodium falciparum was demonstrated by the majority of the compounds. Notably, compounds SZ14 and SZ9 demonstrated particularly potent effects, with compound SZ14 showing IC50 values of 2.84 μM and SZ9 3.22 μM, indicating single-digit micromolar activity. The compounds exhibiting strong antimalarial activity were assessed through enzymatic tests against the cysteine protease enzymes of P. falciparum, falcipain-2 and falcipain-3. The results indicated that SZ14 and SZ9 inhibited PfFP-2 (IC50 values: 4.1 and 5.4 μM, respectively), and PfFP-3 (IC50 values: 4.9 and 6.3 μM, respectively). To confirm the compounds' specificity towards the parasite, we investigated their cytotoxicity against Vero cell lines, revealing strong selectivity indices and no significant cytotoxic effects. Additionally, in vitro hemolysis testing showed these compounds to be non-toxic to normal human blood cells. Moreover, predicted in silico ADME parameters and physiochemical characteristics demonstrated the drug-likeness of the synthetic compounds. These collective findings suggest that sulfonamide derivatives based on pyrimidine-tethered oxospirochromane could serve as templates for the future development of potential antimalarial drugs.

Identification of Spiro[chromene-2,4'-piperidine]s as Potent, Selective, and Gq-Biased 5-HT2C Receptor Partial Agonists

A series of spiropiperidines was designed and synthesized by structural modifications based on our previous lead compound 1 and evaluated with cellular signaling assays for the discovery of 5-HT2C receptor (5-HT2CR) selective agonists with a Gq bias. Structure-activity relationship (SAR) studies of spiropiperidines uncovered spiro[chromene-2,4'-piperidine]s as a novel chemotype of 5-HT2CR selective agonists. Among this new series, the 7-chloro analogue 8 was identified as the most potent and selective 5-HT2CR partial agonist (Emax = 71.09%) with an EC50 value of 121.5 nM and no observed activity toward 5-HT2AR or 5-HT2BR. Moreover, compound 8 exhibited no recruitment activity for β-arrestin and showed low inhibition of hERG at 10 μM. These findings may pave the way to develop more potent Gq-biased 5-HT2CR partial agonists as useful pharmacological tool compounds or potential drug candidates.

Novel spiro[chromanone-2,4'-piperidine]-4-one derivatives as potential inhibitors of fatty acid synthesis in pathogens: Design, synthesis, and biological evaluation

Bacterial survival depends on membrane lipid homeostasis that enables to regulate lipid composition to adapt and optimize their growth in diverse environments. Therefore, the development of inhibitors that interfere with the bacterial fatty acid synthesis process is considered to be a promising tactic. In this study, 58 novel spirochromanone derivatives were prepared and their structure-activity relationship (SAR) was investigated. The bioassay results showed that all most of the compounds showed excellent biological activities, exampled by compounds B₁₄, C₁, B₁₅, and B₁₃, which had outstanding inhibitory activities toward various pathogenic bacteria with EC₅₀ values of 0.78 μg/mL ∼3.48 μg/mL. Preliminary antibacterial behavior was studied by a series of biochemical assays including, but not limited to, fluorescence imaging patterns, GC-MS analysis, TEM images, and fluorescence titration experiments. Notably, compound B₁₄ decreased the lipid content of the cell membrane, and increased cell membrane permeability, thereby destroying the integrity of the bacterial cell membrane. Further qRT-PCR results indicated that compound B₁₄ interfered with the mRNA expression levels of fatty acid synthesis process-related genes including ACC, ACP, and Fab family genes. Herein, we highlight the promising bactericidal skeleton based on the spiro[chromanone-2,4'-piperidine]-4-one as a potential inhibitor of fatty acid synthesis.

Design, Synthesis and Biological Evaluation of Novel Spiro-[chroman-2,4'-piperidin]-4-one Analogues as Anti-Tubercular Agents

A series of novel spiro-[chromane-2,4'-piperidine]-4(3 H )-one derivatives were designed, synthesized and structures were confirmed by analytical methods viz., 1 H NMR, 13 C NMR and Mass spectrometry. Synthesized derivatives were evaluated for their anti-mycobacterial activity against Mycobacterium tuberculosis ( Mtb ) H37Ra strain. Among all the evaluated compounds, PS08 exhibited significant inhibition with MIC value of 3.72 μM while MIC values of the remaining compounds ranged from 7.68 to 230.42 μM in comparison to the standard drug INH (MIC 0.09 μM). The two most active compounds however showed acute cytotoxicity towards the human MRC-5 lung fibroblast cell line. The in-silico ADMET profiles of the titled compounds were predicted and found within the prescribed limits of the Lipinski and Jorgenson rules. Molecular docking study of the significantly active compound ( PS08 ) was also carried out after performing validation in order to understand the putative binding position of the test ligand at the active site of selected target protein Mtb tyrosine phosphatase (PtpB).

Palladium-Catalyzed Three-Component Cascade Reaction of Nitriles: Synthesis of 2-Arylquinoline-4-carboxylates

A new method for converting easy availability starting materials 2-(2-oxoindolin-3-yl)acetonitrile, arylboronic acids, and alcohols into 2-arylquinoline-4-carboxylates is reported. The procedure involves a three-component addition/ring expansion/esterification reaction in the presence of Pd(II) catalyst with high functional group tolerance under mild conditions. In addition, the photophysical properties of the resulting product were investigated and exhibited excellent polarity-sensitive fluorescence properties and AIE property.

Design, synthesis and biological evaluation of 7-(5-((substituted - amino)-methyl)-thiophen-2-yl)-spiro-[chroman-2,4'-piperidin]-4-one hydrochloride analogues as anticancer agents

A series of thirty-one novel 7-(5-((amino)-methyl)-thiophen-2-yl)-spiro-[chroman-2,4'-piperidin]-4-one hydrochloride analogues (Cst 1 - 31) have been designed, synthesized and characterized by ¹H NMR, ¹³C NMR and MS spectral analysis. Here, we evaluated the anticancer potential and biological results of low-molecular-weight bridgehead oxygen and nitrogen-containing spirochromanones on proliferation and apoptosis of the human breast cancer cell line (MCF-7) and Murine melanoma (B16F10). The anticancer activity ranged from 2.9 to 35.0 µM. The most potent compounds Cst-22, Cst-24 and Cst-31 were found to be less toxic against human embryonic kidney (HEK-293) cell lines. Cst-24 and Cst-31 were found to be causing significant cytotoxicity through apoptotic cell death and also G2 phase arrest of cell cycle in B16F10 cells. In-silico ADME prediction stidies of the titled compounds were found within the rules outlined, and these compounds may not face any pharmacokinetic associated issues in the mere future upon developmental stage. These conjugates may serve as a lead for the discovery of potential anticancer drug candidate with better therapeutic profile.

Inhibition of acetyl-CoA carboxylase by PP-7a exerts beneficial effects on metabolic dysregulation in a mouse model of diet-induced obesity

Acetyl-coenzyme A carboxylase (ACC) is a critical regulator of fatty acid metabolism and represents a promising therapeutic target for metabolic diseases, including obesity, type 2 diabetes and non-alcoholic fatty liver disease. Recently, a novel ACC inhibitor, PP-7a, was developed by our group by utilizing a structure-based drug design. In the present study, the pharmacological effects of PP-7a on the metabolic dysregulation in mice with high-fat diet (HFD)-induced obesity and the underlying mechanisms were investigated. The inhibitory effect on ACC activities was confirmed by assessing the level of malonyl-CoA, a product synthesized by the catalyzation of ACC. Following 16 weeks of being fed an HFD, the mice were administered PP-7a (15, 45 or 75 mg/kg) for 4 weeks. The effects of PP-7a on weight gain, glucose intolerance, hepatic lipid accumulation and the increase of serum triglyceride (TG), total cholesterol (TC) and free fatty acids (FFA) in mice were assessed. CP-640186 was used as a positive control drug and administered in the same manner as PP-7a. Chronic administration of PP-7a lowered the malonyl-CoA levels in liver and heart tissues of mice in the HFD group. In addition, HFD-induced weight gain and glucose intolerance were improved by PP-7a treatment in the mice fed the HFD. Furthermore, PP-7a suppressed hepatic lipid accumulation and the increase in TG, TC and FFA levels. Taken together, these results suggest that ACC inhibition by PP-7a may have a beneficial effect on metabolic dysregulation in obese mice.

Design, Synthesis, and Structure-Activity Relationship of Novel Spiropyrimidinamines as Fungicides against Pseudoperonospora cubensis

Harmful fungus and the developed resistance to available fungicides seriously threaten the yield and quality of crops; thus, the search for new, highly efficient, and resistance-overcoming fungicides remains a quite urgent goal of agricultural scientists. In this study, a series of novel spiropyrimidinamine derivatives were designed and synthesized by employing the intermediate derivatization method (IDM). Their structures were identified by ¹H NMR, elemental analyses, and MS spectra. The structure of compound 5 was further confirmed by X-ray diffraction. Bioassays indicated that a number of the title compounds exhibited some fungicidal activities against Pseudoperonospora cubensis. Especially, compound 5 displayed excellent activity (EC₅₀ = 0.422 mg/L), significantly higher than those of the commercialized fungicides cyazofamid, flumorph, and diflumetorim. The structure-activity relationship was also discussed. It was concluded that compound 5 with super fungicidal potency and a novel structure is a promising agrochemical fungicide candidate for further development.

Spirocyclic sulfonamides with carbonic anhydrase inhibitory and anti-neuropathic pain activity

A novel series of 4-oxo-spirochromane bearing primary sulfonamide group were synthetized as Carbonic Anhydrase inhibitors (CAIs) and tested for their management of neuropathic pain. Indeed, CAs have been recently validated as novel therapeutic targets in neuropathic pain. All compounds, here reported, showed strong activity against hCA II and hCA VII with K_I values in the low or sub-nanomolar range. Two compounds (6d and 6l) showed good neuropathic pain attenuating effects and longer duration than drug reference acetazolamide in an animal model of oxaliplatin induced neuropathy.

Insight into the molecular mechanism of yeast acetyl-coenzyme A carboxylase mutants F510I, N485G, I69E, E477R, and K73R resistant to soraphen A

Acetyl-coenzyme A carboxylases (ACCs) is the first committed enzyme of fatty acid synthesis pathway. The inhibition of ACC is thought to be beneficial not only for diseases related to metabolism, such as type-2 diabetes, but also for infectious disease like bacterial infection disease. Soraphen A, a potent allosteric inhibitor of BC domain of yeast ACC, exhibit lower binding affinities to several yeast ACC mutants and the corresponding drug resistance mechanisms are still unknown. We report here a theoretical study of binding of soraphen A to wild type and yeast ACC mutants (including F510I, N485G, I69E, E477R, and K73R) via molecular dynamic simulation and molecular mechanics/generalized Born surface area free energy calculations methods. The calculated binding free energies of soraphen A to yeast ACC mutants are weaker than to wild type, which is highly consistent with the experimental results. The mutant F510I weakens the binding affinity of soraphen A to yeast ACC mainly by decreasing the van der Waals contributions, while the weaker binding affinities of Soraphen A to other yeast ACC mutants including N485G, I69E, E477R, and K73R are largely attributed to the decreased net electrostatic (ΔE_ele + ΔG_GB) interactions. Our simulation results could provide important insights for the development of more potent ACC inhibitors.