A Diverse Series of Substituted Benzenesulfonamides as Aldose Reductase Inhibitors with Antioxidant Activity: Design, Synthesis, and in Vitro Activity

Diverse role, structural trends, and applications of fluorinated sulphonamide compounds in agrochemical and pharmaceutical fields

Our knowledge of fluorine's unique and complex properties has significantly increased over the past 20 years. Consequently, more sophisticated and innovative techniques have emerged to incorporate this feature into the design of potential drug candidates. In recent years, researchers have become interested in synthesizing fluoro-sulphonamide compounds to discover new chemical entities with distinct and unexpected physical, chemical, and biological characteristics. The fluorinated sulphonamide molecules have shown significant biomedical importance. Their potential is not limited to biomedical applications but also includes crop protection. The discovery of novel fluorine and Sulfur compounds has highlighted their importance in the chemical sector, particularly in the agrochemical and medicinal fields. Recently, several fluorinated sulphonamide derivatives have been developed and frequently used by agriculturalists to produce food for the growing global population. These molecules have also exhibited their potential in health by inhibiting various human diseases. In today's world, it is crucial to have a steady supply of innovative pharmaceutical and agrochemical molecules that are highly effective, less harmful to the environment, and affordable. This review summarizes the available information on the activity of Fluorine and Sulphonamide compounds, which have proven active in pharmaceuticals and agrochemicals with excellent environmental and human health approaches. Moreover, it focuses on the current literature on the chemical structures, the application of fluorinated sulphonamide compounds against various pathological conditions, and their effectiveness in crop protection.

Tetrazole derivatives in the management of neurological disorders: Recent advances on synthesis and pharmacological aspects

Neurological disorders are the leading cause of a large number of mortalities and morbidities. Nitrogen heterocyclic compounds have been pivotal in exhibiting wide array of therapeutic applications. Among them, tetrazole is a ubiquitous class of organic heterocyclic compounds that have attracted much attention because of its unique structural and chemical properties, and a wide range of pharmacological activities comprising anti-convulsant effect, antibiotic, anti-allergic, anti-hypertensive to name a few. Owing to significant chemical and biological properties, the present review aimed at highlighting the recent advances in tetrazole derivatives with special emphasis on their role in the management of neurological diseases. Besides, in-depth structure-activity relationships, molecular docking studies, and associated modes of action of tetrazole derivatives evident in in vitro, in vivo preclinical, and clinical studies have been discussed.

Tetrazoles and Related Heterocycles as Promising Synthetic Antidiabetic Agents

Tetrazole heterocycle is a promising scaffold in drug design, and it is incorporated into active pharmaceutical ingredients of medications of various actions: hypotensives, diuretics, antihistamines, antibiotics, analgesics, and others. This heterocyclic system is metabolically stable and easily participates in various intermolecular interactions with different biological targets through hydrogen bonding, conjugation, or van der Waals forces. In the present review, a systematic analysis of the activity of tetrazole derivatives against type 2 diabetes mellitus (T2DM) has been performed. As it was shown, the tetrazolyl moiety is a key fragment of many antidiabetic agents with different activities, including the following: peroxisome proliferator-activated receptors (PPARs) agonists, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase (AR) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) agonists, G protein-coupled receptor (GPCRs) agonists, glycogen phosphorylases (GP) Inhibitors, α-glycosidase (AG) Inhibitors, sodium glucose co-transporter (SGLT) inhibitors, fructose-1,6-bisphosphatase (FBPase) inhibitors, IkB kinase ε (IKKε) and TANK binding kinase 1 (TBK1) inhibitors, and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). In many cases, the tetrazole-containing leader compounds markedly exceed the activity of medications already known and used in T2DM therapy, and some of them are undergoing clinical trials. In addition, tetrazole derivatives are very often used to act on diabetes-related targets or to treat post-diabetic disorders.

Highlights on U.S. FDA-approved fluorinated drugs over the past five years (2018-2022)

The objective of this review is to provide an update on the fluorine-containing drugs approved by U.S. Food and Drug Administration in the span of past five years (2018-2022). The agency accepted a total of fifty-eight fluorinated entities to diagnose, mitigate and treat a plethora of diseases. Among them, thirty drugs are for therapy of various types of cancers, twelve for infectious diseases, eleven for CNS disorders, and six for some other diseases. These are categorized and briefly discussed based on their therapeutic areas. In addition, this review gives a glimpse about their trade name, date of approval, active ingredients, company developers, indications, and drug mechanisms. We anticipate that this review may inspire the drug discovery and medicinal chemistry community in both industrial and academic settings to explore the fluorinated molecules leading to the discovery of new drugs in the near future.

Some sulfonamides as aldose reductase inhibitors: therapeutic approach in diabetes

In this study, aldose reductase (AR) was purified from sheep kidney using chromatographic methods and examined the interactions between some sulfonamides and the enzyme. According to results, sulfonamides display effective inhibitor features for sheep kidney AR with IC₅₀ values in the range of 37.27-87.65 μM and K_is in the range of 25.72 ± 6.45 to 73.56 ± 17.49 μM. The sulfonamides displayed different inhibition mechanisms. It was found that studied all compounds displayed non-competitive inhibition type except for 5-chlorothiophene-2-sulfonamide (1). It showed competitive inhibition. Among these compounds, 2,5-dichlorothiophene-3-sulfonamide compound (2) was showed the most potent AR inhibitor (K_i: 25.72 ± 6.45). These compounds may be useful in the treatment of diabetic complications.

Biological effects of bis-hydrazone compounds bearing isovanillin moiety on the aldose reductase

Aldose reductase (ALR2), one of the metabolically important enzymes, catalyzes the formation of sorbitol from glucose in the polyol pathway. ALR2 inhibition is required to prevent diabetic complications. In the present study, the novel bis-hydrazone compounds bearing isovanillin moiety (GY1-12) were synthesized, and various chromatographic methods were applied to purify the ALR2 enzyme. Afterward, the inhibitory effect of the synthesized compounds on the ALR2 was screened in vitro. All the novel bis-hydrazones demonstrated activity in nanomolar levels as AR inhibitors with IC₅₀ and K_I values in the range of 12.55-35.04 nM, and 13.38-88.21 nM, respectively. Compounds GY-11, GY-7, and GY-5 against ALR2 were identified as the highly potent inhibitors, respectively, and were superior to the standard drug, epalrestat. Moreover, a comprehensive ligand-receptor interactions prediction was performed using ADME-Tox, Glide XP, and MM-GBSA modules of Schrödinger Small-Molecule Drug Discovery Suite to elucidate the novel bis-hydrazone derivatives, potential binding modes versus the ALR2. As a result, these compounds with ALR2 inhibitory effects may be potential alternative agents that can be used to treat or prevent diabetic complications.

Multifunctional agents based on benzoxazolone as promising therapeutic drugs for diabetic nephropathy

Diabetic nephropathy (DN) is resulted from activations of polyol pathway and oxidative stress by abnormal metabolism of glucose, and no specific medication is available. We designed a novel class of benzoxazolone derivatives, and a number of individuals were found to have significant antioxidant activity and inhibition of aldose reductase of the key enzyme in the polyol pathway. The outstanding compound (E)-2-(7-(4-hydroxy-3-methoxystyryl)-2-oxobenzo[d]oxazol-3(2H)-yl)acetic acid was identified to reduce urinary proteins in diabetic mice suggesting an alleviation in the diabetic nephropathy, and this was confirmed by kidney hematoxylin-eosin staining. Further investigations showed blood glucose normalization, declined in the polyol pathway and lipid peroxides, and raised glutathione and superoxide dismutase activity. Thus, we suggest a therapeutic function of the compound for DN which could be attributed to the combination of hypoglycemic, aldose reductase inhibition and antioxidant.

Aldose reductase and protein tyrosine phosphatase 1B inhibitors as a promising therapeutic approach for diabetes mellitus

Diabetes mellitus is a metabolic disease characterized by high blood glucose levels and usually associated with several chronic pathologies. Aldose reductase and protein tyrosine phosphatase 1B enzymes have identified as two novel molecular targets associated with the onset and progression of type II diabetes and related comorbidities. Although many inhibitors against these enzymes have already found in the field of diabetic mellitus, the research for discovering more effective and selective agents with optimal pharmacokinetic properties continues. In addition, dual inhibition of these target proteins has proved as a promising therapeutic approach. A variety of diverse scaffolds are presented in this review for the future design of potent and selective inhibitors of aldose reductase and protein tyrosine phosphatase 1B based on the most important structural features of both enzymes. The discovery of novel dual aldose reductase and protein tyrosine phosphatase 1B inhibitors could be effective therapeutic molecules for the treatment of insulin-resistant type II diabetes mellitus. The methods used comprise a literature survey and X-ray crystal structures derived from Protein Databank (PDB). Despite the available therapeutic options for type II diabetes mellitus, the inhibitors of aldose reductase and protein tyrosine phosphatase 1B could be two promising approaches for the effective treatment of hyperglycemia and diabetes-associated pathologies. Due to the poor pharmacokinetic profile and low in vivo efficacy of existing inhibitors of both targets, the research turned to more selective and cell-permeable agents as well as multi-target molecules.

Novel 2-phenoxypyrido[3,2-b]pyrazin-3(4H)-one derivatives as potent and selective aldose reductase inhibitors with antioxidant activity

To develop multifunctional aldose reductase (AKR1B1) inhibitors for anti-diabetic complications, a novel series of 2-phenoxypyrido[3,2-b]pyrazin-3(4H)-one derivatives were designed and synthesised. Most of the derivatives were found to be potent and selective against AKR1B1, and 2-(7-chloro-2-(3,5-dihydroxyphenoxy)-3-oxopyrido[3,2-b]pyrazin-4(3H)-yl) acetic acid (4k) was the most active with an IC50 value of 0.023 µM. Moreover, it was encouraging to find that some derivatives showed strong antioxidant activity, and among them, the phenolic 3,5-dihydroxyl compound 4l with 7-bromo in the core structure was proved to be the most potent, even comparable to that of the well-known antioxidant Trolox. Thus the results suggested success in the construction of potent and selective AKR1B1 inhibitors with antioxidant activity.

Identification of quinoxalin-2(1H)-one derivatives as a novel class of multifunctional aldose reductase inhibitors

Aim: Targeting aldose reductase and oxidative stress with quinoxalin-2(1 H)-one derivatives having a 1-hydroxypyrazole head as the bioisosteric replacement of carboxylic acid. Methodology & results: Aldose reductase inhibition, selectivity and antioxidant potency of all the synthesized compounds were evaluated, and binding modes were studied by molecular docking. Most of the derivatives showed potent and selective aldose reductase inhibition, and among them 13d was the most active (IC50 = 0.107 μM), suggesting success of the bioisosteric strategy. Phenolic 3,4-dihydroxyl compound 13f showed strong antioxidant ability even comparable to that of the well-known antioxidant Trolox. Conclusion: The present study identified the excellent bioisostere of the 1-hydroxypyrazole head group along with phenolic hydroxyl and vinyl spacer in C3 side chain on constructing quinoxalinone-based multifunctional aldose reductase inhibitors.

Benzoxazinone-thiosemicarbazones as antidiabetic leads via aldose reductase inhibition: Synthesis, biological screening and molecular docking study

Aldose reductase is an important enzyme in the polyol pathway, where glucose is converted to fructose, and sorbitol is released. Aldose reductase activity increases in diabetes as the glucose levels increase, resulting in increased sorbitol production. Sorbitol, being less cell permeable tends to accumulate in tissues such as eye lenses, peripheral nerves and glomerulus that are not insulin sensitive. This excessive build-up of sorbitol is responsible for diabetes associated complications such as retinopathy and neuropathy. In continuation of our interest to design and discover potent inhibitors of aldo-keto reductases (AKRs; aldehyde reductase ALR1 or AKR1A, and aldose reductase ALR2 or AKR1B), herein we designed and investigated a series of new benzoxazinone-thiosemicarbazones (3a-r) as ALR2 and ALR1 inhibitors. Most compounds exhibited excellent inhibitory activities with IC₅₀ values in lower micro-molar range. Compounds 3b and 3l were found to be most active ALR2 inhibitors with IC₅₀ values of 0.52 ± 0.04 and 0.19 ± 0.03 μM, respectively, both compounds were more effective inhibitors as compared to the standard ALR2 inhibitor (sorbinil, with IC₅₀ value of 3.14 ± 0.02 μM).

Fluorine and Fluorinated Motifs in the Design and Application of Bioisosteres for Drug Design

The electronic properties and relatively small size of fluorine endow it with considerable versatility as a bioisostere and it has found application as a substitute for lone pairs of electrons, the hydrogen atom, and the methyl group while also acting as a functional mimetic of the carbonyl, carbinol, and nitrile moieties. In this context, fluorine substitution can influence the potency, conformation, metabolism, membrane permeability, and P-gp recognition of a molecule and temper inhibition of the hERG channel by basic amines. However, as a consequence of the unique properties of fluorine, it features prominently in the design of higher order structural metaphors that are more esoteric in their conception and which reflect a more sophisticated molecular construction that broadens biological mimesis. In this Perspective, applications of fluorine in the construction of bioisosteric elements designed to enhance the in vitro and in vivo properties of a molecule are summarized.

Design, Synthesis and Fungicidal Activity of 2-Substituted Phenyl-2-oxo-, 2-Hydroxy- and 2-Acyloxyethylsulfonamides

Sulfonyl-containing compounds, which exhibit a broad spectrum of biological activities, comprise a substantial proportion of and play a vital role, not only in medicines but also in agrochemicals. As a result increasing attention has been paid to the research and development of sulfonyl derivatives. A series of thirty-eight 2-substituted phenyl-2-oxo- III, 2-hydroxy- IV and 2-acyloxyethylsulfonamides V were obtained and their structures confirmed by IR, ¹H-NMR, and elemental analysis. The in vitro and in vivo bioactivities against two Botrytis cinerea strains, DL-11 and HLD-15, which differ in their sensitivity to procymidone, were evaluated. The in vitro activity results showed that the EC₅₀ values of compounds V-1 and V-9 were 0.10, 0.01 mg L⁻¹ against the sensitive strain DL-11 and 3.32, 7.72 mg L⁻¹ against the resistant strain HLD-15, respectively. For in vivo activity against B. cinerea, compound V-13 and V-14 showed better control effect than the commercial fungicides procymidone and pyrimethanil. The further in vitro bioassay showed that compounds III, IV and V had broad fungicidal spectra against different phytopathogenic fungi. Most of the title compounds showed high fungicidal activities, which could be used as lead compounds for further developing novel fungicidal compounds against Botrytis cinerea.

Isolation, modification, and aldose reductase inhibitory activity of rosmarinic acid derivatives from the roots of Salvia grandifolia

To find aldose reductase inhibitors, two previously unreported compounds, grandifolias H and I, and five known compounds, including rosmarinic acid and rosmarinic acid derivatives, were isolated from the roots of Salvia grandifolia. A series of rosmarinic acid derivatives was obtained from rosmarinic acid using simple synthetic methods. The aldose reductase inhibitory activity of the isolated and synthesized compounds was assessed. Seven of the tested compounds showed moderate aldose reductase inhibition (IC50=0.06-0.30μM). The structure-activity relationship of aldose reductase inhibitory activity of rosmarinic acid derivatives was discussed for the first time. This study provided useful information that will facilitate the development of aldose reductase inhibitors.

Multifunctional aldose reductase inhibitors based on 2H-benzothiazine 1,1-dioxide

A series of benzothiazine derivatives were designed and synthesized for the development of drug candidates for diabetic complications.

Synthesis and Biological Evaluation of Novel Gigantol Derivatives as Potential Agents in Prevention of Diabetic Cataract

As a continuation of our efforts directed towards the development of natural anti-diabetic cataract agents, gigantol was isolated from Herba dendrobii and was found to inhibit both aldose reductase (AR) and inducible nitric oxide synthase (iNOS) activity, which play a significant role in the development and progression of diabetic cataracts. To improve its bioefficacy and facilitate use as a therapeutic agent, gigantol (compound 14f) and a series of novel analogs were designed and synthesized. Analogs were formulated to have different substituents on the phenyl ring (compounds 4, 5, 8, 14a-e), substitute the phenyl ring with a larger steric hindrance ring (compounds 10, 17c) or modify the carbon chain (compounds 17a, 17b, 21, 23, 25). All of the analogs were tested for their effect on AR and iNOS activities and on D-galactose-induced apoptosis in cultured human lens epithelial cells. Compounds 5, 10, 14a, 14b, 14d, 14e, 14f, 17b, 17c, 23, and 25 inhibited AR activity, with IC50 values ranging from 5.02 to 288.8 μM. Compounds 5, 10, 14b, and 14f inhibited iNOS activity with IC50 ranging from 432.6 to 1188.7 μM. Compounds 5, 8, 10, 14b, 14f, and 17c protected the cells from D-galactose induced apoptosis with viability ranging from 55.2 to 76.26%. Of gigantol and its analogs, compound 10 showed the greatest bioefficacy and is warranted to be developed as a therapeutic agent for diabetic cataracts.

Applications of Fluorine in Medicinal Chemistry

The role of fluorine in drug design and development is expanding rapidly as we learn more about the unique properties associated with this unusual element and how to deploy it with greater sophistication. The judicious introduction of fluorine into a molecule can productively influence conformation, pKa, intrinsic potency, membrane permeability, metabolic pathways, and pharmacokinetic properties. In addition, (18)F has been established as a useful positron emitting isotope for use with in vivo imaging technology that potentially has extensive application in drug discovery and development, often limited only by convenient synthetic accessibility to labeled compounds. The wide ranging applications of fluorine in drug design are providing a strong stimulus for the development of new synthetic methodologies that allow more facile access to a wide range of fluorinated compounds. In this review, we provide an update on the effects of the strategic incorporation of fluorine in drug molecules and applications in positron emission tomography.

A direct catalytic ring expansion approach to o-fluoronaphthols and o/p-fluorophenols from indanones and 2-cyclopentenones

A catalytic ring expansion of indanones to o-fluoronaphthols is described by taking advantage of the multi-reactivities of TMSCF₂Br.

Synthesis, nitric oxide release, and α-glucosidase inhibition of nitric oxide donating apigenin and chrysin derivatives

α-Glucosidase (AG) play crucial roles in the digestion of carbohydrates. Inhibitors of α-glucosidase (AGIs) are promising candidates for the development of anti-diabetic drugs. Here, five series of apigenin and chrysin nitric oxide (NO)-donating derivatives were synthesised and evaluated for their AG inhibitory activity and NO releasing capacity in vitro. Except for 9a-c, twelve compounds showed remarkable inhibitory activity against α-glucosidase, with potency being better than that of acarbose and 1-deoxynojirimycin. All organic nitrate derivatives released low concentrations of NO in the presence of l-cysteine. Structure activity relationship studies indicated that 5-OH, hydrophobic coupling chain, and carbonyl groups of the coupling chain could enhance the inhibitory activity. Apigenin and chrysin derivatives therefore represents a new class of promising compounds that can inhibit α-glucosidase activity and supply moderate NO for preventing the development of diabetic complications.

Benzothiazolyl substituted iminothiazolidinones and benzamido-oxothiazolidines as potent and partly selective aldose reductase inhibitors

Two new series of oxothiazolidine benzoate and acetate derivatives were synthesized and evaluated as aldehyde reductase (ALR1) and aldose reductase (ALR2) inhibitors.

Discovery of new selective human aldose reductase inhibitors through virtual screening multiple binding pocket conformations

Aldose reductase reduces glucose to sorbitol. It plays a key role in many of the complications arising from diabetes. Thus, aldose reductase inhibitors (ARI) have been identified as promising therapeutic agents for treating such complications of diabetes, as neuropathy, nephropathy, retinopathy, and cataracts. In this paper, a virtual screening protocol applied to a library of compounds in house has been utilized to discover novel ARIs. IC50's were determined for 15 hits that inhibited ALR2 to greater than 50% at 50 μM, and ten of these have an IC50 of 10 μM or less, corresponding to a rather substantial hit rate of 14% at this level. The specificity of these compounds relative to their cross-reactivity with human ALR1 was also assessed by inhibition assays. This resulted in identification of novel inhibitors with IC50's comparable to the commercially available drug, epalrestat, and greater than an order of magnitude better selectivity.

Synthesis and antigastric ulcer activity of novel 5-isoproyl-3,8-dimethylazulene derivatives

5-Isoproyl-3,8-dimethylazulene derivatives were synthesized and evaluated for antigastric ulcer activity in vivo. Some of them possess the best activity against gastric ulcer with ulcer index values lower than the drug reference (omeprazole). The structure-activity relationship (SAR) shows that the lipophilic flat structure contributes to quite potent antigastric ulcer activity.

Design and synthesis of potent and selective aldose reductase inhibitors based on pyridylthiadiazine scaffold

A series of pyrido[2,3-e]-[1,2,4]-thiadiazine 1,1-dioxide acetic acid derivatives were synthesized and tested for their inhibitory activity against aldose reductase (ALR2). These derivatives were found to be potent aldose reductase inhibitors with IC50 values ranging from 0.038 μM to 11.29 μM. Most but not all of them showed a strong ALR2 inhibition activity and significant selectivity, which were further supported by docking studies. Of these inhibitors, compound 7d exhibited highest inhibition activity. Structure-activity relationship studies indicate the requirement of N2-benzyl group with electron-withdrawing substituents and N4-acetic acid group in the pyridothiadiazine scaffold.