Sulfonamide Analogues Research Articles

Bicyclic core estrogens as full antagonists: synthesis, biological evaluation and structure–activity relationships of estrogen receptor ligands based on bridged oxabicyclic core arylsulfonamides

Compounds that block estrogen action through the estrogen receptor (ER) or downregulate ER levels are useful for the treatment of breast cancer and endocrine disorders. In our search for structurally novel estrogens having three-dimensional core scaffolds, we found some compounds with a 7-oxabicyclo[2.2.1]heptene core that bound well to the ERs. The best of these compounds, a phenyl sulfonate ester (termed OBHS for oxabicycloheptene sulfonate), was a partial antagonist on both ERα and ERβ. Although OBHS bears no structural resemblance to other estrogen antagonists, it appears to achieve its partial antagonist character by stabilizing a novel conformation of the ER that involves a significant distortion of helix-11. To enhance the antagonist properties of these oxabicyclo[2.2.1]heptane core ligands, we expanded the functional diversity of OBHS by replacing the sulfonate with secondary or tertiary sulfonamides (-SO(2)NR-), isoelectronic and potentially isostructural molecular replacements. An array of 16 OBHS sulfonamide analogues were prepared through a Diels-Alder reaction of a 3,4-diarylfuran using various N-aryl vinyl sulfonamide dienophiles. While the more polar secondary sulphonamides were weak ligands, certain of the tertiary sulfonamides had very good ER binding affinity. In HepG2 cell reporter gene assays, the sulphonamides had moderate potency, but they showed lower intrinsic transcriptional activity on ERα than the selective estrogen receptor modulator (SERM) hydroxytamoxifen or OBHS, and they were inverse agonists on ERβ. Thus, the behaviour of these OBH-sulfonamides more closely mirrors the activity of full antagonists like the drug fulvestrant (ICI 182 780), and their greater antagonist biocharacter appears to arise from an accentuated distortion of helix-11.

II. Novel HCV NS5B polymerase inhibitors: Discovery of indole C2 acyl sulfonamides

Development of SAR at the C2 position of indole lead 1, a palm site inhibitor of HCV NS5B polymerase (NS5B IC(50)=0.053μM, replicon EC(50)=4.8μM), is described. Initial screening identified an acyl sulfonamide moiety as an isostere for the C2 carboxylic acid group. Further SAR investigation resulted in identification of acyl sufonamide analog 7q (NS5B IC(50)=0.039μM, replicon EC(50)=0.011μM) with >100-fold improved replicon activity.

SAR of tricyclic sulfones as γ-secretase inhibitors

Novel tricyclic sulfones as γ-secretase inhibitors have been reported by this laboratory for the treatment of Alzheimer’s disease. Compounds in this series have comparable or better in vitro activities and in vivo efficacies than sulfonamide analogues reported previously by this laboratory. Based on the previously reported tricyclic sulfone scaffold, additional SAR studies of C ring were carried out. Various C-ring structures including cyclohexane, pyran, and piperidine were tolerated. Additionally, the 7- and 8- positions of the C-ring were identified as the best sites to introduce substituent for modulating the pharmacokinetic properties of compounds from this series.

Investigation on biological activities of anthranilic acid sulfonamide analogs.

In the previous studies, the cytotoxicities of anthranilate sulfonamides were investigated. Herein, the bioactivities of 4-substituted (X = NO2, OCH3, CH3, Cl) benzenesulfonamides of anthranilic acid (5-8) are reported. The results revealed that all sulfonamides selectively exerted antifungal activity (25-50 % inhibition) against C. albicans at 4 μg/mL. Furthermore, compounds 6 and 8 show antioxidative (SOD) activity. These sulfonamides, except for 6, selectively display cytotoxic effects toward MOLT-3 cells. It is interesting to note that sulfonamides with electron withdrawing substituent (5, X = NO2) exhibited the highest cytotoxicity. This study provided preliminary structure-activity relationship of the anthranilic sulfonamides that is useful for further in-depth investigation.

Rimonabant Redux and Strategies to Improve the Future Outlook of CB1 Receptor Neutral‐Antagonist/Inverse‐Agonist Therapies

Rimonabant Redux and Strategies to Improve the Future Outlook of CB1 Receptor Neutral‐Antagonist/Inverse‐Agonist Therapies

Zonisamide for Migraine Prophylaxis in Topiramate-Intolerant Patients: An Observational Study

Zonisamide, a sulfonamide analog, is an antiepileptic drug with mechanisms of action similar to topiramate. Because of its pharmacodynamic and pharmacokinetics profiles, zonisamide is also potentially suitable for migraine prevention. Tolerability and effectiveness of zonisamide for migraine prophylaxis in patients with a good response to topiramate, but interrupting it for intolerable side effects, were evaluated in 34 patients. After a 1-month period of wash-out, patients were treated with zonisamide (up to a 100 mg/day dosage) for 6 consecutive months. Zonisamide was well tolerated, only 4 (12%) patients reported transient and tolerable side effects. Mean number of days with headache per month was reduced from 14.9 ± 5.3 during the wash-out period to 2.5 ± 0.6 after 6 months of zonisamide (P < .001). We observed a significant reduction in headache severity and disability, as assessed by visual analog scale and migraine disability assessment scale. Finally, when compared with the 1-month period prior to starting zonisamide, a reduced use of analgesics was recorded at the end of the follow-up. Our findings support the use of zonisamide as an alternative therapy for migraine prevention in patients with good response, but poor tolerance to topiramate.

Structural and pharmacological analysis of O-2050, a putative neutral cannabinoid CB1 receptor antagonist

Rimonabant, the prototypic antagonist of cannabinoid CB1 receptors, has been reported to have inverse agonist properties at higher concentrations, which may complicate its use as a tool for mechanistic evaluation of cannabinoid pharmacology. Consequently, recent synthesis efforts have concentrated on discovery of a neutral antagonist using a variety of structural templates. The purpose of this study was to evaluate the pharmacological properties of the putative neutral cannabinoid CB1 receptor antagonist O-2050, a sulfonamide side chain analog of Δ8-tetrahydrocannabinol. O-2050 and related sulfonamide cannabinoids exhibited good affinity for both cannabinoid CB1 and CB2 receptors. While the other sulfonamide analogs produced cannabinoid agonist effects in vivo (e.g., activity suppression, antinociception, and hypothermia), O-2050 stimulated activity and was inactive in the other two tests. O-2050 also decreased food intake in mice, an effect that was reminiscent of that produced by rimonabant. Unlike rimonabant, however, O-2050 did not block the effects of cannabinoid agonists in vivo, even when administered i.c.v. In contrast, O-2050 antagonized the in vitro effects of cannabinoid agonists in [35S]GTPγS and mouse vas deferens assays without having activity on its own in either assay. Further evaluation revealed that O-2050 fully and dose-dependently substituted for Δ9-tetrahydrocannabinol in a mouse drug discrimination procedure (a cannabinoid agonist effect) and that it inhibited forskolin-stimulated cyclic AMP signaling with a maximum efficacy of approximately half that of the full agonist CP55,940 [(-)-cis-3-[2-hydroxy-4(1,1-dimethyl-heptyl)phenyl]-trans-4-(3-hydroxy-propyl)cyclohexanol]. Together, these results suggest that O-2050 is not a viable candidate for classification as a neutral cannabinoid CB1 receptor antagonist.

3D-QSAR study of benzene sulfonamide analogs as carbonic anhydrase II inhibitors

Three-dimensional quantitative structure–activity relationship (3D-QSAR) studies were performed for a series of carbonic anhydrase inhibitors using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. The large set of 37 different aromatic/heterocyclic sulfonamides carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, such as CA II chosen for the present study. The conventional ligand-based 3D-QSAR studies were performed based on the low energy conformations employing database alignment rule. The ligand-based model gave q 2 values 0.538 and 0.527 and r 2 values 0.974 and 0.971 for CoMFA and CoMSIA, respectively, and the predictive ability of the model was validated. The predicted r 2 values are 0.565 and 0.502 for CoMFA and CoMSIA, respectively. Results indicate that the CoMFA and CoMSIA models could be reliable model which may be used in the design of novel carbonic anhydrase inhibitors as leads.

Synthesis and QSAR of Quinazoline Sulfonamides As Highly Potent Human Histamine H4 Receptor Inverse Agonists

Hit optimization of the class of quinazoline containing histamine H(4) receptor (H(4)R) ligands resulted in a sulfonamide substituted analogue with high affinity for the H(4)R. This moiety leads to improved physicochemical properties and is believed to probe a distinct H(4)R binding pocket that was previously identified using pharmacophore modeling. By introducing a variety of sulfonamide substituents, the H(4)R affinity was optimized. The interaction of the new ligands, in combination with a set of previously published quinazoline compounds, was described by a QSAR equation. Pharmacological studies revealed that the sulfonamide analogues have excellent H(4)R affinity and behave as inverse agonists at the human H(4)R. In vivo evaluation of the potent 2-(6-chloro-2-(4-methylpiperazin-1-yl)quinazoline-4-amino)-N-phenylethanesulfonamide (54) (pK(i) = 8.31 +/- 0.10) revealed it to have anti-inflammatory activity in an animal model of acute inflammation.

Genome wide analysis and comparative docking studies of new diaryl furan derivatives against human cyclooxygenase-2, lipoxygenase, thromboxane synthase and prostacyclin synthase enzymes involved in inflammatory pathway

In an effort to develop potent anti-inflammatory and antithrombotic drugs, a series of new 4-(2-phenyltetrahydrofuran-3-yl) benzene sulfonamide analogs were designed and docked against homology models of human cyclooxygenase-2 (COX-2), lipoxygenase and thromboxane synthase enzymes built using MODELLER 7v7 software and refined by molecular dynamics for 2 ns in a solvated layer. Validation of these homology models by procheck, verify-3D and ERRAT programs revealed that these models are highly reliable. Docking studies of 4-(2-phenyltetrahydrofuran-3-yl) benzene sulfonamide analogs designed by substituting different chemical groups on benzene rings replacing 1H pyrazole in celecoxib with five membered thiophene, furan, 1H pyrrole, 1H imidazole, thiazole and 1,3-oxazole showed that diaryl furan molecules showed good binding affinity towards mouse COX-2. Further, docking studies of diaryl furan derivatives are likely to have superior thromboxane synthase and COX-2 selectivity. Docking studies against site directed mutagenesis of Arg120Ala, Ser530Ala, Ser530Met and Tyr355Phe enzymes displayed the effect of inhibition of COX-2. Drug likeliness and activity decay for these inhibitors showed that these molecules act as best drugs at very low concentrations.

Docking and 3D-QSAR Studies on Isatin Sulfonamide Analogues as Caspase-3 Inhibitors

To provide insight of their inhibition mechanism and facilitate the design of more potent ligands, a series of 59 isatin sulfonamide analogues were docked to the X-ray structure of caspase-3, one of the important cysteine aspartyl-specific execution proteases in apoptosis, and their binding conformations were analyzed by 3D-QSAR studies. Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) studies suggest that both steric and electrostatic interactions contribute to the compounds' binding affinity, with the major contribution arising from hydrophobic interactions. The models show excellent correlation and high predictive power even evaluated by the most stringent criteria for a QSAR model. The results of this work demonstrate that structure-based design methods (such as docking) cultivate the development of reliable QSAR models; they also illustrate the utility of this procedure in design of new potent caspase-3 ligands.

Amide Isosteres of Oroidin: Assessment of Antibiofilm Activity and C. elegans Toxicity

The synthesis and antibiofilm activities of sulfonamide, urea, and thiourea oroidin analogues are described. The most active derivative was able to selectively inhibit P. aeruginosa biofilm development and is also shown to be nontoxic upward of 1 mM to the development of C. elegans in comparison to other similar isosteric analogues and the natural product oroidin.

A synthesis of sulfonamide analogs of platensimycin employing a palladium-mediated carbonylation strategy

The monodentate ligand 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phospha-adamantane (PA-Ph) is shown to be highly effective in palladium-catalyzed carbonylative cross-coupling. Aryl and vinyl halides were efficiently converted to carboxylic acids, amides and to primary, secondary, and tertiary esters, respectively. Application of the Pd(OAc) 2/PA-Ph (1:1) catalyst system proved critical in the methoxycarbonylation of a functionalized nitroresorcinol halide, allowing convenient access to novel platensimycin sulfonamide analogs.

18F]- and [11C]-Labeled N-benzyl-isatin sulfonamide analogues as PET tracers for Apoptosis: synthesis, radiolabeling mechanism, and in vivo imaging study of apoptosis in Fas-treated mice using [11C]WC-98

The radiolabeled isatin sulfonamide caspase-3 inhibitor, [18F] 2 (WC-II-89), is a potential PET radiotracer for noninvasive imaging of apoptosis. The radiolabeling mechanism was studied by 13C NMR, ESI/MS, and computational calculations. It was found that the high electrophilicity of the C3 carbonyl group in the isatin ring, which served as a trap for [18F]fluoride, was responsible for the failure of the radiolabeling via nucleophilic substitution of the mesylate group in 7a by [18F]fluoride. Once treated with a strong base, 7a opened the isatin ring completely to form an isatinate intermediate 16, which lost the ability to trap [18F]fluoride, thereby allowing the displacement of the mesylate group to afford the 18F-labeled isatinate 17. [18F] 17 can be converted to isatin [18F] 2 efficiently under acidic conditions. The ring-opening and re-closure of the isatin ring under basic and acidic conditions were confirmed by reversed phase HPLC analysis, ESI/MS and 13C NMR studies. Computational studies of model compounds also support the above proposed mechanism. Similarly, the ring-opening and re-closure method was used successfully in the synthesis of the 11C labeled isatin sulfonamide analogue [11C] 4 (WC-98). A microPET imaging study using [11C] 4 in the Fas liver apoptosis model demonstrated retained activity in the target organ (liver) of the treated mice. Increased caspase-3 activation in the liver was verified by the fluorometric caspase-3 enzyme assay. Therefore, this study provides a useful method for radio-synthesis of isatin derivative radiotracers for PET and SPECT studies, and [11C] 4 is a potential PET radiotracer for noninvasive imaging of apoptosis.

Three Dimensional Quantitative Structure-Activity Relationships of Sulfonamides Binding Monoclonal Antibody by Comparative Molecular Field Analysis

AbstractThe three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MabSMR) produced against sulfamerazine, was carried out by comparative molecular field analysis (CoMFA). The affinities of MabSMR, expressed as Log10IC50, for 17 sulfonamide analogs were determined by competitive fluorescence polarization immunoassay (FPIA). Removal of two outliers from the initial set of 17 sulfonamide analogs improved the predictability of the models. The 3D-QSAR model of 15 sulfonamides resulted in q2cv values of 0.600, and r2 values of 0.995, respectively. This novel study combining FPIA with CoMFA demonstrates that multidisciplinary research can be used as a useful tool to investigate antigen-antibody interactions and provide information required for design of novel haptens, which may result in new antibodies with properties already optimized by an antibody-based immunoassay.

RCAI-17, 22, 24–26, 29, 31, 34–36, 38–40, and 88, the analogs of KRN7000 with a sulfonamide linkage: Their synthesis and bioactivity for mouse natural killer T cells to produce Th2-biased cytokines

RCAI-17, 22, 24–26, 29, 31, 34–36, 38–40, and 88, the analogs of KRN7000 ( 1) with a sulfonamide linkage instead of an amide bond, were synthesized to examine their bioactivity for mouse natural killer (NK) T cells. RCAI-17, 22, 24–26, 29, 31, 34–36, and 88 are the aromatic sulfonamide analogs, while RCAI-39 and 40 are the aliphatic ones. RCAI-38 is a C-galactoside analog of RCAI-26, which is the p-toluenesulfonamide analog of KRN7000. According to their bioassay, these sulfonamide analogs were shown to be the stimulants of mouse NKT cells to induce the production of Th2-biased cytokines in vitro, while RCAI-38 did not induce any cytokine production.

Synthesis of 2‐oxoamides based on sulfonamide analogs of γ‐amino acids and their activity on phospholipase A2

A variety of lipophilic 2-oxoamides containing sulfonamide analogs of gamma-amino acids as well as acyl sulfonamides of gamma-aminobutyric acid were synthesized. Their ability to inhibit intracellular GIVA cPLA2 and GVIA iPLA2 as well as secreted GV sPLA2 was evaluated. The sulfonamide group seems a bioisosteric group suitable to replace the carboxyl group in 2-oxoamide inhibitors of GVIA cPLA2.

Bis(sulfonamide) isosters of mycophenolic adenine dinucleotide analogues: Inhibition of inosine monophosphate dehydrogenase

Synthesis of novel inhibitors of human IMP dehydrogenase is described. These inhibitors are isosteric methylenebis(sulfonamide) analogues 5– 8 of earlier reported mycophenolic adenine methylenebis(phosphonate)s 1– 3. The parent bis(phosphonate) 1 and its bis(sulfonamide) analogue 5 showed similar sub-micromolar inhibitory activity against IMPDH2 ( K i ∼ 0.2 μM). However, the bis(sulfonamide) analogues 6 and 8 substituted at the position 2 of adenine were approximately 3- to 10-fold less potent inhibitors of IMPDH2 ( K i = 0.3–0.4 μM) than the corresponding parent bis(phosphonate)s 2 and 3 ( K i = 0.04–0.11μM), respectively.

The Effect of Antiepileptic Drugs Administered in Pregnancy on Micronucleus Frequency in Cord Blood Lymphocytes

Epidemiological data indicate that the pregnancies of epileptic women constitute about 1% of all pregnancies. A large group of antiepileptic drugs (AEDs) applied in long-term monotherapy or polytherapy produce toxic metabolites as well as free radicals and reactive oxygen species. The aim of this study was to assess the potential genotoxic effect of AED therapy in pregnancy on DNA structure of umbilical cord blood lymphocytes. The study group were 30 newborns (14 males and 16 females) of mothers receiving long-term AED therapy during pregnancy. The AED considered were carbamazepine, valproic acid, phenyltriazine, benzodiazepine, gamma-aminobutyric acid and sulfonamide analogues. The controls were infants born to mothers not exposed to any medication in pregnancy (n = 20). Positive controls were the same infants, but in this case Nitrogranulogen (Sigma) was added to the collected cord blood samples (n = 11). Micronucleus (MN) assay was used as an indicator of chromosome damage. The frequency (%) of MN/1000 binucleated cells and the nuclear division index (NDI) were calculated. Mean MN frequency and NDI were respectively 0.110 (+/-0.152), 1.592 (+/-0.206) in the study group and 0.050 (+/-0.061), 1.628 (+/-0.178) in the controls (statistically non-significant difference, p > 0.1). The findings did not reveal any genotoxic effect or inhibition of nuclear division in cord blood lymphocytes by AED metabolites. This was reflected by the absence of significant between-group differences in the mean MN frequency and NDI.

Isatin Sulfonamide Analogs Containing a Michael Addition Acceptor: A New Class of Caspase 3/7 Inhibitors

A series of isatin sulfonamide analogs having a Michael acceptor were prepared and their potencies for inhibiting caspase-1, -3, -6, -7, and -8 were evaluated. These compounds have nanomolar potency for inhibiting the executioner caspases, caspase-3 and caspase-7, and have a low potency for inhibiting caspase-1, caspase-6, and caspase-8. The inhibition mechanism was investigated through NMR studies of the reaction between 11d and benzylmercaptan as a model for Cys-285 in the active site of caspase-3.