Five-Membered Heterocyclic Sulfonamides as Carbonic Anhydrase Inhibitors

Development of novel amino-benzenesulfonamide derivatives and their analogues as carbonic anhydrase inhibitors: Design, synthesis, anticancer activity assessment, and pharmacokinetic studies using UPLC-MS/MS

The present study outlines the design and synthesis of dual-tail analogues of SLC-0111 as carbonic anhydrase inhibitors (CAIs) targeting tumor isoforms IX and XII 4a-h and 5a-h, along with pharmacokinetic studies. The synthesized compounds were evaluated for their inhibitory activity against four carbonic anhydrase isoforms (hCA I, II, IX, and XII), revealing potent activity, particularly against hCA IX and XII. Notably, compounds 4b, 5a, and 5b demonstrated strong inhibition of hCA IX with Ki values of 20.4, 12.9, and 18.2 nM, respectively, compared to acetazolamide (AAZ), which has a Ki of 25 nM. Additionally, compounds 5a, 5b, 5c, and 5d showed selective inhibition of hCA XII, with Ki values of 26.6, 8.7, 17.2, and 10.9 nM, respectively, relative to AAZ (Ki = 5.7 nM). Moreover, both series were tested for their anti-proliferative activity following the US-NCI protocol against a panel of more than fifty cancer cell lines. Compound 5h met the activity criteria and was automatically scheduled for further evaluation at five concentrations with 10-fold dilutions, revealing high toxicity toward leukemia and lower toxicity against melanoma. In addition, the MTT cytotoxicity assay was performed on 5f, 5d and acetazolamide using WI-38 cells. Furthermore, an in vivo pharmacokinetic study was conducted using UPLC-MS/MS on the most potent derivative, 5d, demonstrating a comparable pharmacokinetic profile compared to the reference drug acetazolamide. Furthermore, molecular docking prediction studies were conducted for the most active compounds, 5d and 5h, to elucidate their interactions with the active site hot spots of the CA isoform.

Discovery of a novel 4-pyridyl SLC-0111 analog targeting tumor-associated carbonic anhydrase isoform IX through tail-based design approach with potent anticancer activity

Introduction: Carbonic anhydrase IX (CA IX) is a tumor-associated enzyme involved in cancer progression and survival. Targeting CA IX with selective inhibitors like SLC-0111 has shown therapeutic potential. This study aimed to develop a novel 4-pyridyl analog (Pyr) of SLC-0111 with enhanced anticancer activity. Methods: Pyr was synthesized using a tail-based design and characterized by NMR. Its cytotoxicity was tested against cancer and normal cell lines. CA inhibition, cell cycle effects, apoptosis induction, and protein expression changes were evaluated. Molecular docking and ADMET predictions assessed binding and drug-like properties. Results and Discussion: Pyr showed selective cytotoxicity toward cancer cells and potent CA IX inhibition. It induced G0/G1 arrest, apoptosis, and modulated p53, Bax, and Bcl-2 levels. Docking confirmed strong CA IX binding, and ADMET analysis indicated good oral bioavailability. These results support Pyr as a promising anticancer candidate.

Exploring the Inhibition of Toxoplasma gondii α-Carbonic Anhydrase by Sulfonamides: Insights into Potential Drug Targeting

Toxoplasma gondii, the causative agent of toxoplasmosis, is a protozoan parasite capable of infecting a wide range of hosts, posing significant health risks, particularly to immunocompromised individuals and congenital transmission. Current therapeutic options primarily target the active tachyzoite stage but are limited by issues such as toxicity and incomplete efficacy. As a result, there is an urgent need for alternative therapies that can selectively target parasite-specific mechanisms critical for metabolic processes and host-parasite interactions. In this context, α-carbonic anhydrase (Tg_CA), an enzyme essential for T. gondii survival has emerged as a promising drug target. Tg_CA was successfully expressed and purified to evaluate its susceptibility to sulfonamide-based inhibitors, represented by compounds 1-24 and the AAZ-HCT series. These inhibitors demonstrated a broad spectrum of activity, with KI values ranging from 17.8 to 8450 nM. Several compounds exhibited moderate to high potency against Tg_CA; however, concerns regarding selectivity arose because of the inhibition of human isoforms, particularly CA I and CA II. Thus, although some inhibitors showed strong activity against Tg_CA, optimizing selectivity remains crucial for minimizing off-target effects and improving therapeutic efficacy. Further structural modifications may enhance selectivity and advance the development of effective treatments for toxoplasmosis.

Development of new chiral 1,2,4-triazole-3-thiones and 1,3,4-thiadiazoles with promising in vivo anticonvulsant activity targeting GABAergic system and voltage-gated sodium channels (VGSCs)

Antiepileptic drugs (AEDs) are used in the treatment of epilepsy, a neurodegenerative disease characterized by recurrent and untriggered seizures that aim to prevent seizures as a symptomatic treatment. However, they still have significant side effects as well as drug resistance. In recent years, especially 1,3,4-thiadiazoles and 1,2,4-triazoles have attracted attention in preclinical and clinical studies as important drug candidates owing to their anticonvulsant properties. Therefore, in this study, which was conducted to discover AED candidate molecules with reduced side effects at low doses, a series of chiral 2,5-disubstituted-1,3,4-thiadiazoles (4a-d) and 4,5-disubstituted-1,2,4-triazole-3 thiones (5a-d) were designed and synthesized starting from l-phenylalanine ethyl ester hydrochloride. The anticonvulsant activities of the new chiral compounds were assessed in several animal seizure models in mice and rats for initial (phase I) screening after their chemical structures including the configuration of the chiral center were elucidated using spectroscopic methods and elemental analysis. First, all chiral compounds were pre-screened using acute seizure tests induced electrically (maximal electroshock test, 6 Hz psychomotor seizure model) and induced chemically (subcutaneous metrazol seizure model) in mice and also their neurotoxicity (TOX) was determined in the rotorad assay. Two of the tested compounds were used for quantitative testing, and (S)-(+)5-[1-(4-fluorobenzamido)-2-phenylethyl]-4-(4-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (5b) and (S)-(+)-(5-[1-(4-fluorobenzamido)-2-phenylethyl]-4-(4-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (5c) emerged as the most promising anticonvulsant drug candidates and also showed low neurotoxicity. The antiepileptogenic potential of these compounds was determined using a chronic seizure induced electrically corneal kindled mouse model. Furthermore, all chiral compounds were tested for their neuroprotective effect against excitotoxic kainic acid (KA) and N-methyl-d-aspartate (NMDA) induced in vitro neuroprotection assay using an organotypic hippocampal slice culture. The KA-induced neuroprotection assay results revealed that compounds 5b and 5c, which are the leading compounds for anticonvulsant activity, also had the strongest neuroprotective effects with IC50 values of 103.30 ± 1.14 and 113.40 ± 1.20 μM respectively. Molecular docking studies conducted to investigate the molecular binding mechanism of the tested compounds on the GABAA receptor showed that compound 5b exhibits a strong affinity to the benzodiazepine (BZD) binding site on GABA. It also revealed that the NaV1.3 binding interactions were consistent with the experimental data and the reported binding mode of the ICA121431 inhibitor. This suggests that compound 5b has a high affinity for these specific binding sites, indicating its potential as a ligand for modulating GABAA and NaV1.3 receptor activity. Furthermore, the ADME properties displayed that all the physicochemical and pharmacological parameters of the compounds stayed within the specified limits and revealed a high bioavailability profile.

Helicase-primase inhibitors for the treatment of herpes simplex virus infections - patent evaluation of WO2023/225162 from Gilead Sciences Inc

Helicase-primase is an interesting target for small-molecule therapy of herpes simplex virus (HSV) infections. With amenamevir already approved for varicella-zoster virus and herpes simplex in Japan and with pritelivir's granted breakthrough therapy designation for the treatment of acyclovir-resistant HSV infections in immunocompromised patients, the target has sparked interest in helicase-primase inhibitors (HPIs). Here, we analyze the first patent application from Gilead in this field, which pursued a me-too approach combining elements from an old Bayer together with a recent Medshine HPI application (which covers the Phaeno Therapeutics drug candidate HN0037). The asset was contributed to Assembly Biosciences, where it is under development as ABI-1179 at the investigational new drug (IND) enabling stage for high-recurrence genital herpes. A structure proposal for indolinoyl derivative ABI-1179 is presented, showing its potential opportunities and limitations compared to other HPIs.

A Novel Compound from the Phenylsulfonylpiperazine Class: Evaluation of In Vitro Activity on Luminal Breast Cancer Cells

Breast cancer (BC) is the most common cancer in women, and is characterized by its histological and molecular heterogeneity. Luminal BC is an estrogen receptor-positive subtype, with varied clinical courses. Although BC patients are eligible for hormone therapy, both early and late relapses still occur, and thus there is a demand for new cytotoxic and selective treatment strategies for these patients. In the present study, inspired by the structure of phenylsulfonylpiperazine, a series of 20 derivatives were tested in bioassays against MCF7, MDA-MB-231 and MDA-MB-453 BC cells to discover new hit compounds. After 48 h of treatment, 12 derivatives impaired cell viability and presented significant IC50 values against at least one of the tumor lineages. Overall, the luminal BC cell line MCF7 was more sensitive to treatments. Compound 3, (4-(1H-tetrazol-1-yl)phenyl)(4-((4-chlorophenyl)sulfonyl)piperazin-1-yl)methanone, was the most promising, with IC50 = 4.48 μM and selective index (SI) = 35.6 in MCF7 cells. Compound 3 also presented significant antimigratory and antiproliferative activities against luminal BC cells, possibly by affecting the expression of genes involved in the epithelial-mesenchymal transition mechanism, upregulating E-Cadherin transcripts (CDH1). Our findings suggest that phenylsulfonylpiperazine derivatives are potential candidates for the development of new therapies, especially those targeting luminal BC.

In-vitro and in-silico investigations of SLC-0111 hydrazinyl analogs as human carbonic anhydrase I, II, IX, and XII inhibitors

Two novel series of hydrazinyl-based benzenesulfonamides 9a-j and 10a-j were designed and synthesized using SLC-0111 as the lead molecule. The newly synthesized compounds were evaluated for their inhibitory activity against four different human carbonic anhydrase (hCA) isoforms I, II, IX, and XII. Both the series reported here were practically inactive against the off-target isozyme hCA I. Notably, derivative 10a exhibited superior potency (Ki of 10.2 nM) than acetazolamide (AAZ) against the cytosolic isoform hCA II. The hCA IX and XII isoforms implicated in tumor progression were effectively inhibited with Kis in the low nanomolar range of 20.5-176.6 nM and 6.0-127.5 nM, respectively. Compound 9g emerged as the most potent and selective hCA IX and XII inhibitor with Ki of 20.5 nM and SI of 200.1, and Ki of 6.0 nM and SI of 683.7, respectively, over hCA I. Furthermore, six compounds (9a, 9h, 10a, 10g, 10i, and 10j) exhibited significant inhibition toward hCA IX (Kis = 27.0, 41.1, 27.4, 25.9, 40.7, and 30.8 nM) relative to AAZ and SLC-0111 (Kis = 25.0 and 45.0 nM, respectively). These findings underscore the potential of these derivatives as potent and selective inhibitors of hCA IX and XII over the off-target hCA I and II.

New 1,3,4-Thiadiazole Derivatives as α-Glucosidase Inhibitors: Design, Synthesis, DFT, ADME, and In Vitro Enzymatic Studies

Diabetes is an emerging disorder in the world and is caused due to the imbalance of insulin production as well as serious effects on the body. In search of a better treatment for diabetes, we designed a novel class of 1,3,4-thiadiazole-bearing Schiff base analogues and assessed them for the α-glucosidase enzyme. In the series (1-12), compounds are synthesized and 3 analogues showed excellent inhibitory activity against α-glucosidase enzymes in the range of IC50 values of 18.10 ± 0.20 to 1.10 ± 0.10 μM. In this series, analogues 4, 8, and 9 show remarkable inhibition profile IC50 2.20 ± 0.10, 1.10 ± 0.10, and 1.30 ± 0.10 μM by using acarbose as a standard, whose IC50 is 11.50 ± 0.30 μM. The structure of the synthesized compounds was confirmed through various spectroscopic techniques, such as NMR and HREI-MS. Additionally, molecular docking, pharmacokinetics, cytotoxic evaluation, and density functional theory study were performed to investigate their behavior.

Sulfonamide derivatives with benzothiazole scaffold: Synthesis and carbonic anhydrase I-II inhibition properties

The secondary sulfonamide derivatives containing benzothiazole scaffold (1-10) were synthesized to determine their inhibition properties on two physiologically essential human carbonic anhydrases isoforms (hCAs, EC, 4.2.1.1), hCA I, and hCA II. The inhibitory effects of the compounds on hCA I and hCA II isoenzymes were investigated by comparing their IC50 and Ki values. The Ki values of compounds (1-10) against hCA I and hCA II are in the range of 0.052 ± 0.022-0.971 ± 0.280 and 0.025 ± 0.010-0.682 ± 0.335, respectively. Some of these inhibited the enzyme more effectively than the standard drug, acetazolamide. In particular, compounds 5 and 4 were found to be most effective on hCA I and hCA II.

Thiosuccinimide enabled S-N bond formation to access N-sulfenylated sulfonamide derivatives with synthetic diversity

A thiosuccinimide enabled S-N cross-coupling strategy has been established for the intermolecular N-sulfenylation of clinically approved sulfa drugs under additive-free conditions. This approach features simple operation, high chemoselectivity for sulfenylating the phenylamino group of sulfonamides, wide substrate scope, and easy scale production, affording N-sulfenylated products in moderate to excellent yields (up to 90%). In addition, we also found that this transformation can be realized in a one-pot manner by employing readily available thiols as starting materials, and the obtained sulfonamide derivatives are capable of various late-stage functionalizations, including oxidation, arylation, benzylation, and methylation.