Discovery of Halogenated Benzothiadiazine Derivatives with Anticancer Activity*

Nickel Pincer Complexes Catalyzed Sustainable Synthesis of 3,4-Dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxides via Acceptorless Dehydrogenative Coupling of Primary Alcohols

We report the atom-economic and sustainable synthesis of biologically important 3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide (DHBD) derivatives from readily available aromatic primary alcohols and 2-aminobenzenesulfonamide catalyzed by nickel(II)-N∧N∧S pincer-type complexes. The synthesized nickel complexes have been well-studied by elemental and spectroscopic (FT-IR, NMR, and HRMS) analyses. The solid-state molecular structure of complex 2 has been authenticated by a single-crystal X-ray diffraction study. Furthermore, a series of 3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide derivatives have been synthesized (24 examples) utilizing a 3 mol % Ni(II) catalyst through acceptorless dehydrogenative coupling of benzyl alcohols with benzenesulfonamide. Gratifyingly, the catalytic protocol is highly selective with the yield up to 93% and produces eco-friendly water/hydrogen gas as byproducts. The control experiments and plausible mechanistic investigations indicate that the coupling of the in situ generated aldehyde with benzenesulfonamide leads to the desired product. In addition, a large-scale synthesis of one of the thiadiazine derivatives unveils the synthetic usefulness of the current methodology.

In vitro antitumor activity, molecular dynamics simulation, DFT study, ADME prediction, and Eg5 binding of enastron analogues

The objective of this study is to evaluate a series of molecules based on cyclosulfamide as potential anticancer agents. Additionally, the study aims to analyze the obtained results through in silico studies; by conducting experiments and utilizing theoretical methods. In this context, we investigated the cytotoxic activity of enastron analogues on three human cell lines PRI (lymphoblastic cell line) derived from B-cell lymphoma. JURKAT (ATCC TIB-152) acute T cell leukaemia and K562 (ATCC CLL-243) is a chronic myelogenous leukaemia. Most of the tested compounds showed good inhibitory activity compared with the reference ligand (chlorambucil). The 5a derivative demonstrated the strongest effect against all cancer cells used. Furthermore, molecular docking simulations of the Eg5-enastron analogue complex revealed that studied molecules have the ability to inhibit the Eg5 enzyme, as evidenced by their calculated docking score. Following the promising results from the molecular docking study, the complex Eg5-4a underwent a 100 ns molecular dynamics simulation using Desmond. During the simulation, the receptor-ligand pairing demonstrated substantial stability after the initial 70 ns. In addition, we used DFT calculations to analyze the electronic and geometric characteristics of the studied compounds. The HOMO and LUMO band gap energies, and the molecular electrostatic potential surface were also deducted for the stable structure of each compound. Also, we studied the prediction of absorption, distribution, metabolism and excretion (ADME) of the compounds.

Selective carbonic anhydrase IX and XII inhibitors based around a functionalized coumarin scaffold

Inhibition of specific carbonic anhydrase (CA) enzymes is a validated strategy for the development of agents to target cancer. The CA isoforms IX and XII are overexpressed in various human solid tumors wherein they play a critical role in regulating extracellular tumor acidification, proliferation, and progression. A series of novel sulfonamides based on the coumarin scaffold were designed, synthesized and characterized as potent and selective CA inhibitors. Selected compounds show significant activity and selectivity over CA I and CA II to target the tumor-associated CA IX and CA XII with high inhibition activity at the single digit nanomolar level. Twelve compounds were identified to be more potent compared with acetazolamide (AAZ) control to inhibit CA IX while one was also more potent than AAZ to inhibit CA XII. Compound 18f (Ki's = 955 nM, 515 nM, 21 nM and 5 nM for CA's I, II, IX, and XII, respectively) is highlighted as a novel CA IX and XII inhibitor for further development.

Chlorinated benzothiadiazines inhibit angiogenesis through suppression of VEGFR2 phosphorylation

Angiogenesis inhibitors are a critical pharmacological tool for the treatment of solid tumors. Suppressing vascular permeability leads to inhibition of tumor growth, invasion, and metastatic potential by blocking the supply of oxygen and nutrients. Disruption of the vascular endothelial growth factor (VEGF) signaling pathway is a validated target for the design of antiangiogenic agents. Several VEGFR2 inhibitors have been clinically approved over the past years. Structural analysis of these clinical VEGFR2 inhibitors highlighted key functional group overlap with the benzothiadiazine core contained in a library of in-house compounds. Herein we ascribe anti-angiogenic activity to a series of chlorinated benzothiadiazines. Selected compounds show significant activity to completely ameliorate VEGF-induced endothelial cell proliferation by suppression of VEGFR2 phosphorylation. The scaffold is devoid of activity to inhibit carbonic anhydrases and generally lacks cytotoxicity across a range of cancer and non-malignant cell lines. Assay of activity at 468 kinases shows remarkable selectivity with only four kinases inhibited > 65% at 10 µM concentration, and with significant activity to inhibit TNK2/ACK1 and PKRD2 by > 90%. All four identified kinase targets are known modulators of angiogenesis, thus highlighting compound 17b as a novel angiogenesis inhibitor for further development.

In Silico Drug Design of Benzothiadiazine Derivatives Interacting with Phospholipid Cell Membranes

The use of drugs derived from benzothiadiazine, a bicyclic heterocyclic benzene derivative, has become a widespread treatment for diseases such as hypertension, low blood sugar or the human immunodeficiency virus, among others. In this work we have investigated the interactions of benzothiadiazine and four of its derivatives designed in silico with model zwitterionic cell membranes formed by dioleoylphosphatidylcholine, 1,2-dioleoyl-sn-glycero-3-phosphoserine and cholesterol at the liquid–crystal phase inside aqueous potassium chloride solution. We have elucidated the local structure of benzothiadiazine by means of microsecond molecular dynamics simulations of systems including a benzothiadiazine molecule or one of its derivatives. Such derivatives were obtained by the substitution of a single hydrogen site of benzothiadiazine by two different classes of chemical groups, one of them electron-donating groups (methyl and ethyl) and another one by electron-accepting groups (fluorine and trifluoromethyl). Our data have revealed that benzothiadiazine derivatives have a strong affinity to stay at the cell membrane interface although their solvation characteristics can vary significantly—they can be fully solvated by water in short periods of time or continuously attached to specific lipid sites during intervals of 10–70 ns. Furthermore, benzothiadiazines are able to bind lipids and cholesterol chains by means of single and double hydrogen-bonds of characteristic lengths between 1.6 and 2.1 Å.