Flow synthesis and biological activity of aryl sulfonamides as selective carbonic anhydrase IX and XII inhibitors

Novel benzenesulfonamide derivatives as potential selective carbonic anhydrase IX, XII inhibitors with anti-proliferative activity: Design, synthesis and in silico studies

As inhibitors of carbonic anhydrases (CAs) IX and XII, a novel series of 1,2,3-triazole benzenesulfonamide derivatives 17a-l containing pyrazolyl-thiazole moiety was designed, synthesized, and tested for anti-proliferative activity. Compounds 17e-h demonstrated more effective inhibitory activity than acetazolamide (IC50 63 nM CA IX and IC50 92 nM CA XII), with IC50 range of 25-52 nM against CA IX and IC50 range of 31-80 nM against CA XII. To verify selectivity against CA IX and CA XII, carbonic anhydrase inhibitory activity of compounds 17e-h against the physiological CA I and CA II isoforms was carried out. The results showed that compounds 17e-h induced lower inhibitory activity against CA I and CA II with IC50 range of 0.428-0.638 μM (CA I) and 0.095-0.164 μM (CA II), in addition to higher selectivity indices (CA I/CA IX S.I. 8.9-19.92, CA I/CA XII S.I. 5.78-16.06) and (CA II/CA IX S.I. 2.83-4.35, CA II/CA XII S.I. 2.05-3.15) when compared to that of acetazolamide, IC50 of 0.199 μM (CA I), 0.133 μM (CA II) (CA I/CA IX S.I. 3.15, CA I/CA XII S.I. 2.16) and (CA II/CA IX S.I. 2.11, CA II/CA XII S.I. 1.44). Concerning anti-proliferative activity of compounds 17e-h, investigations were done on HEPG-2 cell line with IC50 ranges of 3.44-15.03 μM in comparison, 5-FU and doxorubicin showed IC50 values of 11.80 and 9.53 μM, respectively. Furthermore IC50 of MCF-7 and MDA-MB-231 were determined under both normoxic and hypoxic conditions with IC50 values ranging from 3.18-8.26 μM MCF-7 (normoxic), 1.39-6.05 μM MCF-7 (hypoxic), 7.13-26.3 μM MDA-MB-231 (normoxic), 0.76-16.3 μM MDA-MB-231 (hypoxic) using acetazolamide and SLC-0111 as selective CA inhibition references. Moreover, compounds 17e-h demonstrated greater safety against the normal cell line, MCF-10A, with IC50 of 23.06-99.50 μM in comparison to 5-FU and doxorubicin IC50 of 59.8 and 71.8 μM respectively. They also demonstrated (MCF-7 S.I. range of 3.77-31.28) in contrast to doxorubicin (S.I. 13.72) and (HepG-2 S.I. range of 3.60-6.95) in comparison to doxorubicin (S.I. 7.53). In relation to CA IX, XII inhibition, molecular docking of and ADME studies of sulfonamide derivatives 17a-l with CA IX (PDB: 5FL6) and CA XII (PDB: 1JD0) was carried out. Additionally, molecular dynamic simulation was carried out for compounds 17e and 17g which maintained good stability inside the active sites of both enzymes, with average RMSDs of 2.3 Å and 2.1 Å, respectively.

Ring-Opening Reactions of Imidazolidines and Hexahydropyrimidines with Grignard Reagents

We herein report an unprecedented ring-opening of unstrained cyclic aminals such as imidazolidines and hexahydropyrimidines by the use of Grignard and cuprate reagents to give secondary sulfonamides bearing diversely substituted tertiary amines in the β- or γ-position. This synthetic procedure can be carried out in a one-pot fashion without collateral reactions that are commonly associated with sp3-organometallic multicomponent Mannich-type reactions, indicating the fundamental role of sulfonamide protection of the second nitrogen atom in the generation of the cyclic aminal and in the ring-opening process. Computational density functional theory (DFT) data point to the formation of a transient iminium ion intermediate, in which the Lewis acidity of the cationic component of the organometallic reagent triggers the ring-opening process by coordination. The presented method allows the nucleophilic decoration of diamines including those bearing an adjacent chiral center to the tertiary amine not easily achievable by means of alternative standard synthetic procedures.

Facile synthesis, larvicidal activity, biological effects, and molecular docking of sulfonamide-incorporating quaternary ammonium iodides as acetylcholinesterase inhibitors against Culex pipiens L

Insecticides participate with a vital role in our lives especially in preventing the spread of human diseases via controlling the dangerous pests. It is a challenge to identify alternatives to the ordinary insecticides with new mode of action to be used for mosquitoes' control in an environmentally sustainable manner. Using a facile two-step procedure, three novel series of sulfonamide-incorporating quaternary ammonium iodides (3a-i, 4a-i and 5a-i) were synthesized and their chemical structures were successfully characterized. The uncharged sulfonamide intermediates (2a-i) were constructed through simple amidation of the corresponding (hetero)aryl sulfonyl chlorides then the cationic target molecules were formed by quaternizing the tertiary nitrogen with methyl, ethyl, and allyl iodides. The larvicidal activities and biological effects of most synthesized compounds against Culex pipiens L. were extensively investigated and they exhibited good and comparable activities to temephos. Among these hybrids, 4a showed the most potent activity with LC₅₀ = 26.71 ppm. Additionally, the developmental durations of larval and pupal stages were significantly prolonged after treatment with all concentrations of 4h. At high concentration (160 ppm) of 4a and 4b, no adults emerged due to the complete death of pupae, and consequently zero growth index. Moreover, the results of the molecular docking demonstrated that the activities of compounds correlate partially to their binding with acetylcholinesterase (AChE) and it is not the sole parameter for determining the activity.

Design, synthesis and mechanistic study of new benzenesulfonamide derivatives as anticancer and antimicrobial agents via carbonic anhydrase IX inhibition

Changes in gene expression cause uncontrolled cell proliferation and consequently tumor hypoxia. The tumor cells shift their metabolism to anaerobic glycolysis with a significant modification in pH. Therefore, an over expression of carbonic anhydrase IX (CA IX) genes was detected in many solid tumors. Accordingly, selective inhibition of CA IX can be a useful target for discovering novel antiproliferative agents. The present study described the synthesis of new aryl thiazolone–benzenesulfonamides 4a–j as well as their carbonic anhydrase IX inhibitory effect. All the designed derivatives were evaluated for their anti-proliferative activity against triple-negative breast cancer cell line (as MDA-MB-231) and another breast cancer cell line (MCF-7) in addition to normal breast cell line MCF-10A. Compounds 4b–c, 4e, 4g–h showed significant inhibitory effect against both cancer cell lines at concentration ranges from 1.52–6.31 μM, with a high selectivity against breast cancer cell lines ranges from 5.5 to 17.5 times. Moreover, three sulfonamides derivatives 4e, 4g and 4h showed excellent enzyme inhibition against CA IX with IC₅₀ 10.93–25.06 nM and against CA II with IC₅₀ 1.55–3.92 μM that revealed their remarkable selectivity for CA IX over CA II. Additionally, 4e was able to induce apoptosis in MDA-MB-231 with a significant increase in the annexin V-FITC percent by 22 fold as compared with control. Cellular uptake on MDA-MB-231 cell lines were carried out using HPLC method on the three active compounds (4e, 4g and 4h). On the other hand inhibition of one or more CAs present in bacteria was reported to interfere with bacterial growth. So, the new benzenesulfonamides were evaluated against their antibacterial and anti-biofilm activities. Analogues 4e, 4g and 4h exhibited significant inhibition at 50 μg mL⁻¹ concentration with 80.69%, 69.74% and 68.30% against S. aureus compared to the positive control CIP which was 99.2%, while compounds 4g and 4h showed potential anti-biofilm inhibition 79.46% and 77.52% against K. pneumonia. Furthermore, the designed compounds were docked into CA IX (human) protein (PDB ID: 5FL6) and molecular modeling studies revealed favorable binding interactions for the active inhibitors. Finally, the predictive ADMET studies showed that, compounds 4e, 4g and 4h possessed promising pharmacokinetic properties.

New benzenesulfonamide derivatives as anticancer and antimicrobial agents via CA IX inhibition.

New chalcone-sulfonamide hybrids exhibiting anticancer and antituberculosis activity

New sulfonamides 5/6 derived from 4-methoxyacetophenone 1 were synthesized by N-sulfonation reaction of ammonia (3) and aminopyrimidinone (4) with its sulfonyl chloride derivative 2. Sulfonamides 5 and 6 were used as precursors of two new series of chalcones 8a-f and 9a-f, which were obtained through Claisen-Schmidt condensation with aromatic aldehydes 7a-f. Compounds 5/6, 8a-d, 8f, 9a-d, and 9f were screened by the US National Cancer Institute (NCI) at 10 μM against sixty different human cancer cell lines (one-dose trial). Chalcones 8b and 9b satisfied the pre-determined threshold inhibition criteria and were selected for screening at five different concentrations (100, 10, 1.0, 0.1, and 0.01 μM). Compound 8b exhibited remarkable GI₅₀ values ranging from 0.57 to 12.4 μM, with cytotoxic effects being observed in almost all cases, especially against the cell lines K-562 of Leukemia and LOX IMVI of Melanoma with GI₅₀ = 0.57 and 1.28 μM, respectively. Moreover, all compounds were screened against Mycobacterium tuberculosis H37Rv, chalcones 8a-c and 9a-c were the most active showing MIC values between 14 and 42 μM, and interestingly they were devoid of antibacterial activity against Mycobacterium smegmatis and Staphylococcus aureus. These antituberculosis hits showed however low selectivity, being equally inhibitory to M. tuberculosis and mammalian T3T cells. The chalcone-sulfonamide hybrids 8a-f and 9a-f resulted to be appealing cytotoxic agents with significant antituberculosis activity.

5-Arylisothiazol-3(2H)-one-1,(1)-(di)oxides: A new class of selective tumor-associated carbonic anhydrases (hCA IX and XII) inhibitors

Sixteen 5-aryl-substituted isothiazol-3(2H)-one-1,(1)-(di)oxide analogs have been prepared from the corresponding 5-chloroisothiazol-3(2H)-one-1-oxide or -1,1-dioxide by a Suzuki-Miyaura cross-coupling reaction and screened for their inhibition potency against four human carbonic anhydrase isoenzymes: the transmembrane tumor-associated hCA IX and XII and the cytosolic off-target hCA I and II. Most of the synthesized derivatives inhibited hCA IX and XII isoforms in nanomolar range, whereas remained inactive or modestly active against both hCA I and II isoenzymes. In the N-tert-butylisothiazolone series, the 5-phenyl-substituted analog (1a) excelled in the inhibition of tumor-associated hCA IX and XII (K_i = 4.5 and K_i = 4.3 nM, respectively) with excellent selectivity against off target hCA I and II isoenzymes (S > 2222 and S > 2325, respectively). Since the highest inhibition activities were observed with N-tert-butyl derivatives, lacking a zinc-binding group, we suppose to have a new binding mode situated out of the active site. Additionally, three free-NH containing analogs (3a, 4a, 3i) have also been prepared in order to study the impact of free-NH containing N-acyl-sulfinamide- (-SO-NH-CO-) or N-acyl-sulfonamide-type (-SO₂-NH-CO-) derivatives on the inhibitory potency and selectivity. Screening experiments evidenced 5-phenylisothiazol-3(2H)-one-1,1-dioxide (4a), the closest saccharin analog, to be the most active derivative with inhibition constants of K_i = 40.3 nM and K_i = 9.6 nM against hCA IX and hCA XII, respectively. The promising biological results support the high potential of 5-arylisothiazolinone-1,(1)-(di)oxides to be exploited for the design of potent and cancer-selective carbonic anhydrase inhibitors.

Inhibition of carbonic anhydrase IX targets primary tumors, metastases, and cancer stem cells: Three for the price of one

Human carbonic anhydrase (CA) IX is a tumor-associated protein, since it is scarcely present in normal tissues, but highly overexpressed in a large number of solid tumors, where it actively contributes to survival and metastatic spread of tumor cells. Due to these features, the characterization of its biochemical, structural, and functional features for drug design purposes has been extensively carried out, with consequent development of several highly selective small molecule inhibitors and monoclonal antibodies to be used for different purposes. Aim of this review is to provide a comprehensive state-of-the-art of studies performed on this enzyme, regarding structural, functional, and biomedical aspects, as well as the development of molecules with diagnostic and therapeutic applications for cancer treatment. A brief description of additional pharmacologic applications for CA IX inhibition in other diseases, such as arthritis and ischemia, is also provided.

N-Substituted and ring opened saccharin derivatives selectively inhibit transmembrane, tumor-associated carbonic anhydrases IX and XII

A series of N-substituted saccharins incorporating aryl, alkyl and alkynyl moieties, as well as some ring opened derivatives were prepared and investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). The widespread cytosolic isoforms CA I and II were not inhibited by these sulfonamides whereas transmembrane, tumor-associated ones were effectively inhibited, with K_Is in the range of 22.1-481nM for CA IX and of 3.9-245nM for hCA XII. Although the inhibition mechanism of these tertiary/secondary sulfonamides is unknown for the moment, the good efficacy and especially selectivity for the inhibition of the tumor-associated over the cytosolic, widespread isoforms, make these derivatives of considerable interest as enzyme inhibitors with various pharmacologic applications.

Identification and characterization of antibacterial compound(s) of cockroaches (Periplaneta americana)

Infectious diseases remain a significant threat to human health, contributing to more than 17 million deaths, annually. With the worsening trends of drug resistance, there is a need for newer and more powerful antimicrobial agents. We hypothesized that animals living in polluted environments are potential sources of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of microbes, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances. Here, we characterized antibacterial properties in extracts of various body organs of cockroaches (Periplaneta americana) and showed potent antibacterial activity in crude brain extract against methicillin-resistant Staphylococcus aureus and neuropathogenic Escherichia coli K1. The size-exclusion spin columns revealed that the active compound(s) are less than 10 kDa in molecular mass. Using cytotoxicity assays, it was observed that pre-treatment of bacteria with lysates inhibited bacteria-mediated host cell cytotoxicity. Using spectra obtained with LC-MS on Agilent 1290 infinity liquid chromatograph, coupled with an Agilent 6460 triple quadruple mass spectrometer, tissues lysates were analysed. Among hundreds of compounds, only a few homologous compounds were identified that contained the isoquinoline group, chromene derivatives, thiazine groups, imidazoles, pyrrole-containing analogs, sulfonamides, furanones, and flavanones and known to possess broad-spectrum antimicrobial properties and anti-inflammatory, anti-tumour, and analgesic properties. Further identification, characterization, and functional studies using individual compounds can act as a breakthrough in developing novel therapeutics against various pathogens including superbugs.

Methyl-2-methyl-2-(4-methyl-phenyl)sulfonamido propanoate: structural study, supramolecular architecture and analysis of molecular surface electrostatic potential

An arylsulfonamide compound, methyl-2-methyl-2-(4-methylphenyl)sulfonamido propanoate, (1), has been synthesised and structurally characterised. Compound (1) has a staggered conformation relative to the S–N bond. The DFT-optimised molecular geometry of (1) agrees closely with that obtained from the crystallographic study. The crystal exhibits cooperation of N–H···O hydrogen bonds with C–H···O and C–H···π(arene) interactions, resulting in a three-dimensional framework featuring R2 2(8) and R2 2(10) synthons. The effect of substitution in different arylsulfonamides retrieved from the Cambridge Structural Database (CSD) on the formation of supramolecular synthons has been analysed in terms of graph-set notation. Hydrogen-bond based interactions in (1) have been complemented by molecular electrostatic potential (MEP) surface calculation. Hirshfeld surface analyses of (1) and a few related arylsulfonamides retrieved from the CSD indicate that about 80% of the Hirshfeld surface areas in these compounds are due to H···H and O···H contacts.

Adamantane derivatives of sulfonamide molecular crystals: structure, sublimation thermodynamic characteristics, molecular packing, and hydrogen bond networks

The crystal structures of six adamantane derivatives of sulfonamides have been determined by X-ray diffraction and their sublimation and fusion processes have been studied.