Synthesis of new sulfonamides as lipoxygenase inhibitors

Comparative biological activity study of non-radical vs stable radical of pyridazine-sulfonamide aminophenol type compound

4-(3,5-Di-tert-butyl-2-hydroxyphenylamino)-N-(6-methoxypyridazin-3-yl)benzenesulfonamide (LSOAPH2), an 2-aminophenol appended redox non-innocent molecule, is structurally characterized by spectroscopic data and has been confirmed by single crystal X-ray diffraction measurement. The o-Iminosemiquinonate monoanion (LSOISQ) is obtained...

Synthesis and evaluation of novel S-benzyl- and S-alkylphthalimide- oxadiazole -benzenesulfonamide hybrids as inhibitors of dengue virus protease

Direct acting antiviral drugs (DAADs) are becoming therapeutics of choice for the treatment of viral infections. Successful development of anti HIV and HCV drugs by targeting the viral proteases has provided impetus for discovering newer DAADs. Dengue virus (DENV) protease, which is composed of two nonstructural proteins, NS2B and NS3pro, can be likewise exploited for discovering new anti-dengue therapeutics. In this study, we have linked together two pharmaceutically interesting motifs, namely 1,3,4-oxadiazole and benzenesulfonamide in two alternative series to develop novel S-benzylated and S-alkylphthalimidated hybrids. For the first series of hybrids, 4-aminobenzoic acid (1) was reacted with substituted benzenesulfonyl chlorides via its amino group, whereas the carboxylic acid side was elaborated to sulfonamido-1,3,4-oxadiazole-2-thiols (6a/b) in three steps. At this stage, the intermediates 6a/b were bifurcated to either S-alkylphthalimidated (8a-j) or S-benzylated (9a-c) hybrids by reacting with corresponding halides. For the alternative series of hybrids, the carboxylic acid group of probenecid (10) was similarly elaborated to sulfonamido-1,3,4-oxadiazole-2-thiols (13), and diverged to S-alkylphthalimidated (14a-f) and S-benzylated hybrids (15a-e). Bioactivity assays demonstrated that 8g and 8h are the most potent inhibitors among the synthesized analogs, exhibiting the IC50 values of 13.9 μM and 15.1 μM, respectively. Computational assessment predicted the binding of the inhibitors at an allosteric site developed in the open conformation of DENV2 NS2B/NS3pro. Taken together these findings point out that the synthesized hybrid inhibitors possess a great potential for further antiviral drug development.

A Facile and Eco-Friendly Method for the Synthesis of Sulfonamide and Sulfonate Carboxylic Acid Derivatives—X-ray Structure, Hirshfeld Analysis and Spectroscopic Characterizations

The search for a simple and efficient method for the synthesis of sulfonamide and sulfonate derivatives under mild and eco-friendly conditions is of continuing interest. Sulfonyl chlorides are still the best choice as starting materials for the preparation of target products. Here, we report a simple, efficient and eco-friendly method for the synthesis of sulfonamide and sulfonate carboxylic acid derivatives under green conditions using water and sodium carbonate as HCl scavengers to produce the products with high yields and purities. Two derivatives, 4-(tosyloxy)benzoic acid (5a) and 4-((4-methylphenyl)sulfonamido)benzoic acid (5b), were reacted with 2-morpholinoethan-1-amine under green conditions, where OxymaPure/diisopropylcarbodiimide (DIC) was used as a coupling reagent and 2-MeTHF as a solvent to give the target product with high yield and purity. nuclear magnetic resonance (NMR) and elemental analysis confirmed the structures of all obtained products. X-ray crystallography confirmed the structures of products 4b, 4c and 7a. The molecular packing of the three compounds (4b, 4c and 7a) was analyzed using Hirshfeld topology analysis. Mainly, H…O hydrogen bonding interactions dominated the packing. These methods of preparation and coupling merit further attention for the development of new derivatives that might have significant biological applications.

Discovery of a benzenesulfonamide-based dual inhibitor of microsomal prostaglandin E2 synthase-1 and 5-lipoxygenase that favorably modulates lipid mediator biosynthesis in inflammation

Leukotrienes (LTs) and prostaglandin (PG)E2, produced by 5-lipoxygenase (5-LO) and microsomal prostaglandin E2 synthase-1 (mPGES-1), respectively, are key players in inflammation, and pharmacological suppression of these lipid mediators (LM) represents a strategy to intervene with inflammatory disorders. Previous studies revealed that the benzenesulfonamide scaffold displays efficient 5-LO-inhibitory properties. Here, we structurally optimized benzenesulfonamides which led to an N-phenylbenzenesulfonamide derivative (compound 47) with potent inhibitory activities (IC50 = 2.3 and 0.4 μM for isolated 5-LO and 5-LO in intact cells, respectively). Compound 47 prevented the interaction of 5-LO with its activating protein (FLAP) at the nuclear envelope in transfected HEK293 cells as shown by in situ proximity ligation assay. Comprehensive assessment of the LM profile produced by human macrophages revealed the ability of 47 to selectively down-regulate pro-inflammatory LMs (i.e. LTs and PGE2) in M1 but to enhance the formation of pro-resolving LMs (i.e. resolvins and maresins) in M2 macrophages. Moreover, 47 strongly inhibited LT formation and cell infiltration in two in vivo models of acute inflammation (i.e., peritonitis and air pouch sterile inflammation in mice). Together, 47 represents a novel LT biosynthesis inhibitor with an attractive pharmacological profile as anti-inflammatory drug that also promotes the biosynthesis of pro-resolving LM.

Synthesis and evaluation of sulfonamide-bearing thiazole as carbonic anhydrase isoforms hCA I and hCA II

Sulfonamide-bearing thiazole compounds were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase I and II were evaluated. Human carbonic anhydrase isoenzymes (hCA-I and hCA-II) were purified from erythrocyte cells by affinity chromatography. The inhibitory effects of the 12 synthesized sulfonamide (5a-l) on the hydratase and esterase activities of these isoenzymes (hCA-I and hCA-II) were studied in vitro. In relation to these activities, the inhibition equilibrium constants (Ki) were determined. The results showed that all the synthesized compounds inhibited the CA isoenzyme activity. Among them 5b was found to be the most active (IC50 = 0.35 μM; Ki: 0.33 μM) for hCA I and hCA II.

Synthesis, crystal structure, spectroscopic and density functional theory (DFT) study of N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine

N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine has been synthesized and characterized by various spectroscopic techniques including FT-IR, UV-vis, (1)H-NMR, (13)C-NMR spectroscopy, and the structure was unequivocally confirmed by single crystal X-ray diffraction studies. The compound crystallized in monoclinic system with P21/n space group, and adopted cis-geometry around the azomethine CN double bond. The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H⋯O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance. Absorption wavelength was studied by scanning UV-vis. absorption spectrum in different solvents to explore excited state stability of the molecule in polar solvent. Density functional theory calculations were performed at B3LYP/6-31G (d, p) level in order to compare the experimental results with the theoretical results. The simulated molecular electrostatic potential (MEP), Mulliken charges and NPA (natural population analysis) also confirmed the presence of specific intermolecular hydrogen bonding (C-H⋯O). In addition natural bond orbital (NBO) analysis (intra and inter molecular bonding and interaction among bonds), frontier molecular orbital analysis (electronic properties) and first hyperpolarizability analysis (nonlinear optical response) were simulated at B3LYP/6-31G (d, p) level of theory.

15-Lipoxygenase inhibition of Commelina benghalensis, Tradescantia fluminensis, Tradescantia zebrina

OBJECTIVE

To evaluate the 15-lipoxygenase inhibitory activity of the methanol leaf extracts of Commelina benghalensis, Tradescantia fluminensis (T. fluminensis) and Tradescantia zebrina.

METHOD

The inhibitory activity was evaluated using a spectrophotometric assay by observing the increase in absorbance at 234 nm due to the formation of the product 13-hydroperoxyoctadecadienoic acid. The extracts were also tested for the presence of terpenoids, saponins, tannins, flavonoids, steroids, phenolic compounds, alkaloids and cardiac glycosides.

RESULTS

All the extracts inhibited the action of 15-lipoxygenase at a concentration of 0.2 µg/mL. T. fluminensis and Tradescantia zebrina exhibited higher than 50% inhibition with T. fluminensis at 87.2%. T. fluminensis was partitioned with ethyl acetate and hexane and their IC50 values were determined at 8.72 µg/mL and 98.04 µg/mL, respectively.

CONCLUSIONS

T. fluminensis is a potentially good source of 15-lipoxygenase inhibitors.

Crystal structure ofN-(1-allyl-3-chloro-4-ethoxy-1H-indazol-5-yl)-4-methoxybenzenesulfonamide

In the title compound, C₁₉H₂₀ClN₃O₄S, the benzene ring is inclined to the indazole ring system (r.m.s. deviation = 0.014 Å) by 65.07 (8)°. The allyl and eth­oxy groups are almost normal to the indazole ring, as indicated by the respective torsion angles [N—N—C—C = 111.6 (2) and C—C—O—C = −88.1 (2)°]. In the crystal, mol­ecules are connected by N—H⋯N hydrogen bonds, forming helical chains propagating along [010]. The chains are linked by C—H⋯O hydrogen bonds, forming a three-dimensional network.

Crystal structure of N-(3-chloro-1-methyl-1H-indazol-5-yl)-4-meth-oxy-benzene-sulfonamide

In the title compound, C₁₅H₁₄ClN₃O₃S, the dihedral angle between the planes of the indazole ring system (r.m.s. deviation = 0.007 Å) and the benzene ring is 89.05 (7)°. The meth­oxy C atom deviates from its attached ring by 0.196 (3) Å. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds generate R₂²(8) loops. The dimers are connected into [010] chains by C—H⋯O inter­actions.

Crystal structure of N-(1-allyl-3-chloro-1H-indazol-5-yl)-4-methyl-benzene-sulfonamide

The 3-chloro-1H-indazole system in the title mol­ecule, C₁₇H₁₆ClN₃O₂S, is almost planar, with the largest deviation from the mean plane being 0.029 (2) Å for one of the N atoms. This system is nearly perpendicular to the allyl chain, as indicated by the C—C—N—N torsion angle of −90.1 (6)° between them. The allyl group is split into two fragments, the major component has a site occupancy of 0.579 (7). The indazole system makes a dihedral angle of 47.53 (10)° with the plane through the benzene ring. In the crystal, mol­ecules are connected by N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network.

Synthesis, biological evaluation and docking study of 3-aroyl-1-(4-sulfamoylphenyl)thiourea derivatives as 15-lipoxygenase inhibitors

A series of 3-aroyl-1-(4-sulfamoylphenyl)thiourea derivatives containing sulfonamide moiety were designed and synthesized as 15-lipoxygenase (15-LOX) inhibitors. Most synthesized compounds showed potent activity against soybean 15-LOX with IC50 values less than 25 μM. The most potent compound 4c (3-methylbenzoyl derivative) with IC50 value of 1.8 μM was 10-fold more potent than quercetin. Interestingly, compound 4c also showed the highest antioxidant activity, as determined by ferric reducing antioxidant power (FRAP) assay. Its capacity for reducing ferric ion was more than ascorbic acid. The viability assay of the selected compound 4c against oxidative stress-induced cell death in differentiated PC12 cells revealed that compound 4c significantly protected neurons against cell death in low concentrations.

N-(1-Allyl-3-chloro-4-ethoxy-1H-indazol-5-yl)-4-methylbenzenesulfonamide

In the title compound, C₁₉H₂₀ClN₃O₃S, the benzene ring is inclined to the indazole ring system by 51.23 (8)°. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers which stack in columns parallel to [011]. The atoms in the allyl group are disordered over two sets of sites with an occupancy ratio of 0.624 (8):0.376 (8).

N-(3-Chloro-4-eth-oxy-1-methyl-1H-indazol-5-yl)-4-meth-oxy-benzene-sulfonamide

The indazole ring system of the title compound, C17H18ClN3O4S, is almost planar (r.m.s. deviation = 0.0113 Å) and forms dihedral angles of 32.22 (8) and 57.5 (3)° with the benzene ring and the mean plane through the 4-eth-oxy group, respectively. In the crystal, mol-ecules are connected by pairs of N-H⋯O hydrogen bonds into inversion dimers, which are further linked by π-π inter-actions between the diazole rings [inter-centroid distance = 3.4946 (11) Å], forming chains parallel to [101].

N-(3-Chloro-1-methyl-1H-indazol-5-yl)-4-methylbenzene-sulfonamide

The asymmetric unit of the title compound, C15H14ClN3O2S, contains two independent mol-ecules showing different conformations: in one mol-ecule, the indazole ring system makes a dihedral angle of 51.5 (1)° with the benzene ring whereas in the other, the indazole unit is almost perpendicular to the benzene ring [dihedral angle 77.7 (1)°]. In the crystal, the mol-ecules are linked by N-H⋯N and N-H⋯O hydrogen bonds, forming a set of four mol-ecules linked in pairs about an inversion centre.

N-(1-Allyl-1H-indazol-5-yl)-4-methylbenzenesulfonamide

The asymmetric unit of the title compound, C₁₇H₁₇N₃O₂S, contains two independent mol­ecules linked by an N—H⋯O hydrogen bond. The mol­ecules show different conformations. In the first mol­ecule, the fused five- and six-membered ring system is almost perpendicular to the plane through the atoms forming the allyl group, as indicated by the dihedral angle of 85.1 (4)°. The dihedral angle with the methyl­benzene­sulfonamide group is 78.8 (1)°. On the other hand, in the second mol­ecule, the dihedral angles between the indazole plane and the allyl and methyl­benzene­sulfonamide groups are 80.3 (3) and 41.5 (1)°, respectively. In the crystal, mol­ecules are further linked by N—H⋯N and C—H⋯O hydrogen bonds, forming a three-dimensional network.

4-Methyl-N-(1-methyl-1H-indazol-5-yl)benzenesulfonamide

In the title compound, C₁₅H₁₅N₃O₂S, the fused ring system is close to planar, the largest deviation from the mean plane being 0.030 (2) Å, and makes a dihedral angle of 48.84 (9)° with the benzene ring belonging to the methyl­benzene­sulfonamide moiety. In the crystal, mol­ecules are ­connected through N—H⋯N hydrogen bonds and weak C—H⋯O contacts, forming a two-dimensional network parallel to (001).