Synthesis and Anti-Chikungunya Virus (CHIKV) Activity of Novel 1,4-Naphthoquinone Sulfonamide and Sulfonate Ester Derivatives

Chikungunya virus (CHIKV) is a re-emerging disease caused by an alphavirus of the Togaviridae family. Since its first description in 1952, the disease has spread worldwide, affecting populations in both tropical and temperate countries. To date, there is no licensed vaccine or specific pharmacological treatment. Therefore, there is an increasing urgency in developing new antiviral drugs capable of specifically inhibiting viral replication. In the present work, we report the synthesis and antiviral activity evaluation of nineteen naphthoquinone derivatives, containing a sulfonamide or sulfonate group. Cell viability assays indicated a low toxic potential for all tested compounds and inhibitory assays against CHIKV identified five compounds with potent activity. The compounds were also evaluated for their virucidal potential, and the results demonstrated that compound 11a exhibited a virucidal effect higher than 70% in the treatment with 20 µM. Furthermore, in silico studies were performed to predict the antiviral drug targets.

Structural characterization of naphthalene sulfonamides and a sulfonate ester and their in vitro efficacy against Leishmania tarentolae promastigotes

Structural and biological activity analyses of two naphthalene sulfonamides and a naphthalene sulfonate ester.

ROS Inhibitory Activity and Cytotoxicity Evaluation of Benzoyl, Acetyl, Alkyl Ester, and Sulfonate Ester Substituted Coumarin Derivatives

Background: A number of non-steroidal anti-inflammatory drugs (NSAIDs) including aspirin, indomethacin, ibuprofen, flufenamic acid, and phenylbutazone are being clinically used to treat inflammatory disorders. These NSAIDs are associated with serious side effects such as gastric ulceration, nephrotoxicity, and bleeding. Therefore, the identification of potent and safe therapy for inflammatory disorders is still of great interest to the medicinal chemist. Methods: A series of varyingly substituted benzoyl, acetyl, alkyl ester, and sulfonate ester substituted coumarins 1-64 were screened for the inhibition of ROS, generated from zymosan activated whole blood phagocytes, using luminol-enhanced chemiluminescence technique. Results: Among all tested compounds, 8 (IC50 = 65.0 ± 3.1 μM), 24 (IC50 = 41.8 ± 1.5 μM), 26 (IC50 = 10.6 ± 2.8 μM), 28 (IC50 = 20.9 ± 1.5 μM), and 41 (IC50 = 4.6 ± 0.3 μM) showed good anti- inflammatory potential as compared to standard antiinflammatory drug ibuprofen (IC50 = 54.3 ± 1.9 μM). Specifically, compounds 24, 26, 28, and 41 showed superior activity than standard antiinflammatory drug. Furthermore, compounds 12 (IC50 = 219.0 ± 1.4 μM), 14 (IC50 = 216.5 ± 6.2 μM), 16 (IC50 = 187.4 ± 2.2 μM), and 20 (IC50 = 196.2 ± 2.0 μM) showed moderate ROS inhibitory activity. Limited SAR study revealed that the hydroxy-substituted compound showed better ROS inhibition potential in case of 3-benzoyl and 3-ethylester coumarin derivatives. Whereas, chloro substitution was found to be important in case of 3-acetyl coumarin derivatives. Similarly, in case of sulfonate ester, chloro, and nitro groups especially at positions -4 and -3 of ring “R” played vital role in ROS inhibition. Furthermore, cytotoxicity of all active compounds was also checked on NIH-3T3 cell line. Compounds 12, 14, and 20 were found to be non-cytotoxic. Whereas, 8, 16, 24, 26, 28, and 41 were found to be very weak cytotoxic as compared to standard cycloheximide (IC50 = 0.13 ± 0.02 μM). Conclusion: Identified ROS inhibitors offer the possibility of additional modifications that could give rise to lead structures for further research in order to obtain more potent, and safer antiinflammatory agent.

Selective Binding of a Lower Lysine Methylation State: An N,N-Dimethyllysine Selective Host Molecule and Its Use in Methyl Proteomics

<p>Post-translational modifications (PTMs) are critical controllers of protein functions. One set of important PTMs are <i>N</i>-methylated side chains of lysine and arginine, which exist in several functionally distinct forms. Multiple groups have demonstrated the selective binding of the most hydrophobic family member, trimethyllysine (Kme3), using various macrocyclic hosts, but the selective binding of lower methylation states remains challenging. Herein we report that a new calixarene modification – the installation of a sulfonate ester at the lower rim of <i>p</i>-sulfonatocalix[4]arene —efficiently generates a <i>N,N</i>-dimethyllysine (Kme2)-selective host. We characterize its binding behaviors in solution, and demonstrate its effectiveness in a pan-methyllysine enrichment step that enables the observation of hundreds of otherwise unobservable methylation marks in global proteomics experiments.</p><p>The submission includes a manuscript preprint, supporting information, and a tabulation of proteomics data.</p>

Selective Binding of a Lower Lysine Methylation State: An N,N-Dimethyllysine Selective Host Molecule and Its Use in Methyl Proteomics

<p>Post-translational modifications (PTMs) are critical controllers of protein functions. One set of important PTMs are <i>N</i>-methylated side chains of lysine and arginine, which exist in several functionally distinct forms. Multiple groups have demonstrated the selective binding of the most hydrophobic family member, trimethyllysine (Kme3), using various macrocyclic hosts, but the selective binding of lower methylation states remains challenging. Herein we report that a new calixarene modification – the installation of a sulfonate ester at the lower rim of <i>p</i>-sulfonatocalix[4]arene —efficiently generates a <i>N,N</i>-dimethyllysine (Kme2)-selective host. We characterize its binding behaviors in solution, and demonstrate its effectiveness in a pan-methyllysine enrichment step that enables the observation of hundreds of otherwise unobservable methylation marks in global proteomics experiments.</p><p>The submission includes a manuscript preprint, supporting information, and a tabulation of proteomics data.</p>

Oxidative ring-opening of benzothiazole derivatives

An oxidative ring opening of benzothiazole to an acylamidobenzene sulfonate ester using alcohol solvents and magnesium monoperxoyphthalate hexahydrate has been described. Under the established conditions, the reaction produces synthetically significant yields with a variety of benzothiazole derivatives. A sulfonate ester intermediate suggests that the reaction proceeds via thiazole ring opening followed by thiol oxidation.