343-60-2

Upstream product

• 321-14-2 5-chloro-2-hydroxybenzoic acid 
• 371-40-4 4-fluoroaniline 
• 15216-81-6 5-chloro-2-hydroxybenzoyl chloride 

Downstream Products

• 1426258-51-6 4-chloro-2-(4-fluorophenylcarbamoyl)phenyl pyrazine-2-carboxylate 
• 1403607-31-7 4-chloro-2-(4-fluorophenylcarbamoyl)phenyl 4-(trifluoromethyl)benzoate 
• 1422904-41-3 C₂₀H₁₃ClFNO₃ 
• 1552270-29-7 4-chloro-2-[(4-fluorophenyl)carbamoyl]phenyl diethyl phosphate 

Relevant academic research and scientific papers

Application of niclosamide and analogs as small molecule inhibitors of Zika virus and SARS-CoV-2 infection

Zika virus has emerged as a potential threat to human health globally. A previous drug repurposing screen identified the approved anthelminthic drug niclosamide as a small molecule inhibitor of Zika virus infection. However, as antihelminthic drugs are generally designed to have low absorption when dosed orally, the very limited bioavailability of niclosamide will likely hinder its potential direct repurposing as an antiviral medication. Here, we conducted SAR studies focusing on the anilide and salicylic acid regions of niclosamide to improve physicochemical properties such as microsomal metabolic stability, permeability and solubility. We found that the 5-bromo substitution in the salicylic acid region retains potency while providing better drug-like properties. Other modifications in the anilide region with 2′-OMe and 2′-H substitutions were also advantageous. We found that the 4′-NO2 substituent can be replaced with a 4′-CN or 4′-CF3 substituents. Together, these modifications provide a basis for optimizing the structure of niclosamide to improve systemic exposure for application of niclosamide analogs as drug lead candidates for treating Zika and other viral infections. Indeed, key analogs were also able to rescue cells from the cytopathic effect of SARS-CoV-2 infection, indicating relevance for therapeutic strategies targeting the COVID-19 pandemic.

Bio-evaluation of fluoro and trifluoromethyl-substituted salicylanilides against multidrug-resistant S. aureus

Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Staphylococcus aureus (VRSA) are primary causes of skin and soft tissue infections worldwide. To address the emergency caused due to increasing multidrug-resistant (MDR) bacterial infections, a series of novel fluoro and trifluoromethyl-substituted salicylanilide derivatives were synthesized and their antimicrobial activity was investigated. MIC data reveal that the compounds inhibited S. aureus specifically (MIC 0.25–64 μg/mL). The in vitro cytotoxicity of compounds with MIC 1 μg/mL against Vero cells led to identification of four compounds (20, 22, 24 and 25) with selectivity index above 10. These four compounds were tested against MDR S. aureus panel. Remarkably, 5-chloro-N-(4’-bromo-3’-trifluoromethylphenyl)-2-hydroxybenzamide (22) demonstrated excellent activity against nine MRSA and three VRSA strains with MIC 0.031–0.062 μg/mL, which is significantly better than the control drugs methicillin and vancomycin. The comparative time–kill kinetic experiment revealed that the effect of bacterial killing of 22 is comparable with vancomycin. Compound 22 did not synergize with or antagonize any FDA-approved antibiotic and reduced pre-formed S. aureus biofilm better than vancomycin. Overall, study suggested that 22 could be further developed as a potent anti-staphylococcal therapeutic. [Figure not available: see fulltext.]

Discovery and Structure Relationships of Salicylanilide Derivatives as Potent, Non-acidic P2X1 Receptor Antagonists

Antagonists for the ATP-gated ion channel receptor P2X1 have potential as antithrombotics and for treating hyperactive bladder and inflammation. In this study, salicylanilide derivatives were synthesized based on a screening hit. P2X1 antagonistic potency was assessed in 1321N1 astrocytoma cells stably transfected with the human P2X1 receptor by measuring inhibition of the ATP-induced calcium influx. Structure-activity relationships were analyzed, and selectivity versus other P2X receptor subtypes was assessed. The most potent compounds, N-[3,5-bis(trifluoromethyl)phenyl]-5-chloro-2-hydroxybenzamide (1, IC50 0.0192 μM) and N-[3,5-bis(trifluoromethyl)phenyl]-4-chloro-2-hydroxybenzamide (14, IC50 0.0231 μM), displayed >500-fold selectivity versus P2X2 and P2X3, and 10-fold selectivity versus P2X4 and P2X7 receptors, and inhibited collagen-induced platelet aggregation. They behaved as negative allosteric modulators, and molecular modeling studies suggested an extracellular binding site. Besides selective P2X1 antagonists, compounds with ancillary P2X4 and/or P2X7 receptor inhibition were discovered. These compounds represent the first potent, non-acidic, allosteric P2X1 receptor antagonists reported to date.

Phenolic N-monosubstituted carbamates: Antitubercular and toxicity evaluation of multi-targeting compounds

The research of novel antimycobacterial drugs represents a cutting-edge topic. Thirty phenolic N-monosubstituted carbamates, derivatives of salicylanilides and 4-chlorophenol, were investigated against Mycobacterium tuberculosis H37Ra, H37Rv including multidrug- and extensively drug-resistant strains, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium aurum and Mycobacterium smegmatis as representatives of nontuberculous mycobacteria (NTM) and for their cytotoxic and cytostatic properties in HepG2 cells. Since salicylanilides are multi-targeting compounds, we determined also inhibition of mycobacterial isocitrate lyase, an enzyme involved in the maintenance of persistent tuberculous infection. The minimum inhibitory concentrations were from ≤0.5 μM for both drug-susceptible and resistant M. tuberculosis and from ≤0.79 μM for NTM with no cross-resistance to established drugs. The presence of halogenated salicylanilide scaffold results into an improved activity. We have verified that isocitrate lyase is not a key target, presented carbamates showed only moderate inhibitory activity (up to 18% at a concentration of 10 μM). Most of the compounds showed no cytotoxicity for HepG2 cells and some of them were without cytostatic activity. Cytotoxicity-based selectivity indexes of several carbamates for M. tuberculosis, including resistant strains, were higher than 125, thus favouring some derivatives as promising features for future development.

2-Hydroxy-N-Phenylbenzamides and their esters inhibit acetylcholinesterase and Butyrylcholinesterase

The development of novel inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) represents a viable approach to alleviate Alzheimer’s disease. Thirty-six halogenated 2-hydroxy-N-phenylbenzamides (salicylanilides) with various substitution patterns and their esters with phosphorus-based acids were synthesized in yields of 72% to 92% and characterized. They were evaluated for in vitro inhibition of AChE from electric eel and BuChE from equine serum using modified Ellman’s spectrophotometric method. The benzamides exhibited a moderate inhibition of AChE with IC50 values in a narrow concentration range from 33.1 to 85.8 μM. IC50 values for BuChE were higher (53.5–228.4 μM). The majority of derivatives inhibit AChE more efficiently than BuChE and are comparable or superior to rivastigmine—an established cholinesterases inhibitor used in the treatment of Alzheimer’s disease. Phosphorus-based esters especially improved the activity against BuChE with 5-chloro-2-{[4-(trifluoromethyl)phenyl]carbamoyl}phenyl diethyl phosphite 5c superiority (IC50 = 2.4 μM). This derivative was also the most selective inhibitor of BuChE. It caused a mixed inhibition of both cholinesterases and acted as a pseudo-irreversible inhibitor. Several structure-activity relationships were identified, e.g., favouring esters and benzamides obtained from 5-halogenosalicylic acids and polyhalogenated anilines. Both 2-hydroxy-N-phenylbenzamides and esters share convenient physicochemical properties for blood-brain-barrier penetration and thus central nervous system delivery.

Salicylanilide N-monosubstituted carbamates: Synthesis and in vitro antimicrobial activity

The research of innovative antimicrobial agents represents a cutting edge topic. Hence, we synthesized and characterised novel salicylanilide N-monosubstituted carbamates. Twenty compounds were evaluated in vitro against eight bacterial strains and eight fungal species. The lowest minimum inhibitory concentrations (MICs) were found to be ≤0.49 μM. Genus Staphylococcus, including methicillin-resistant Staphylococcus aureus, and fungus Trichophyton mentagrophytes showed uniformly the highest rate of susceptibility, whilst Gram-negative bacteria and most of the fungi were less susceptible. A wide range of carbamates provided comparable or superior in vitro antimicrobial activity in comparison to established drugs. Interestingly, extended-spectrum β-lactamase producing strain of Klebsiella pneumoniae was inhibited with MICs starting from 31.25 μM. With respect to Staphylococci, 2-[(4-bromophenyl)carbamoyl]-4-chlorophenyl phenylcarbamate exhibited the lowest MIC values (≤0.98 μM). 2-[(4-Bromophenyl)carbamoyl]-4-chlorophenyl benzylcarbamate showed the widest spectrum of antifungal action. The results indicate that some salicylanilide carbamates can be considered to be promising candidates for future investigation.

CHEMICAL MODULATORS OF SIGNALING PATHWAYS AND THERAPEUTIC USE

Described are methods of treating a disease associated with dysregulation of the Wnt/Frizzled signaling pathway. The methods include identifying subjects in need of therapy, administering inhibitors of the Wnt/Frizzled signaling pathway, pharmaceutical compositions including the inhibitors, and methods of using the compounds and compositions for treating cancer, bacterial and viral infection, lupus, type II diabetes, nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver disease (NAFLD) in a subject.

Salicylanilide diethyl phosphates as cholinesterases inhibitors

Based on the presence of dialkyl phosphate moiety, we evaluated twenty-seven salicylanilide diethyl phosphates (diethyl [2-(phenylcarbamoyl)phenyl] phosphates) for the inhibition of acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.) and butyrylcholinesterase (BChE) from equine serum. Ellman's spectrophotometric method was used. The inhibitory activity (expressed as IC50 values) was compared with that of the established drugs galantamine and rivastigmine. Salicylanilide diethyl phosphates showed significant activity against both cholinesterases with IC50 values from 0.903 to 86.3 μM. IC50s for BChE were comparatively lower than those obtained for AChE. All of the investigated compounds showed higher inhibition of AChE than rivastigmine, and six of them inhibited BChE more effectively than both rivastigmine and galantamine. In general, derivatives of 4-chlorosalicylic acid showed enhanced activity when compared to derivatives of 5-halogenated salicylic acids, especially against BChE. The most effective inhibitor of AChE was O-{5-chloro-2-[(3-bromophenyl)carbamoyl]phenyl} O,O-diethyl phosphate with IC50 of 35.4 μM, which is also one of the most potent inhibitors of BChE. O-{5-Chloro-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphate exhibited in vitro the strongest inhibition of BChE (0.90 μM). Salicylanilide diethyl phosphates act as pseudo-irreversible cholinesterases inhibitors.

Structure-activity studies of Wnt/β-catenin inhibition in the Niclosamide chemotype: Identification of derivatives with improved drug exposure

The Wnt signaling pathway plays a key role in regulation of organ development and tissue homeostasis. Dysregulated Wnt activity is one of the major underlying mechanisms responsible for many diseases including cancer. We previously reported the FDA-approved anthelmintic drug Niclosamide inhibits Wnt/β-catenin signaling and suppresses colon cancer cell growth in vitro and in vivo. Niclosamide is a multi-functional drug that possesses important biological activity in addition to inhibition of Wnt/β-catenin signaling. Here, we studied the SAR of Wnt signaling inhibition in the anilide and salicylamide region of Niclosamide. We found that the 4′-nitro substituent can be effectively replaced by trifluoromethyl or chlorine and that the potency of inhibition was dependent on the substitution pattern in the anilide ring. Non-anilide, N-methyl amides and reverse amide derivatives lost significant potency, while acylated salicylamide derivatives inhibited signaling with potency similar to non-acyl derivatives. Niclosamide's low systemic exposure when dosed orally may hinder its use to treat systemic disease. To overcome this limitation we identified an acyl derivative of Niclosamide, DK-520 (compound 32), that significantly increased both the plasma concentration and the duration of exposure of Niclosamide when dosed orally. The studies herein provide a medicinal chemical foundation to improve the pharmacokinetic exposure of Niclosamide and Wnt-signaling inhibitors based on the Niclosamide chemotype. The identification of novel derivatives of Niclosamide that metabolize to Niclosamide and increase its drug exposure may provide important research tools for in vivo studies and provide drug candidates for treating cancers with dysregulated Wnt signaling including drug-resistant cancers. Moreover, since Niclosamide is a multi-functional drug, new research tools such as DK520 could directly result in novel treatments against bacterial and viral infection, lupus, and metabolic diseases such as type II diabetes, NASH and NAFLD.

Salicylanilide diethyl phosphates: Synthesis, antimicrobial activity and cytotoxicity

A series of 27 salicylanilide diethyl phosphates was prepared as a part of our on-going search for new antimicrobial active drugs. All compounds exhibited in vitro activity against Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium strains, with minimum inhibitory concentration (MIC) values of 0.5-62.5 μmol/L. Selected salicylanilide diethyl phosphates also inhibit multidrug-resistant tuberculous strains at the concentration of 1 μmol/L. Salicylanilide diethyl phosphates also exhibited mostly the activity against Gram-positive bacteria (MICs ≥1.95 μmol/L), whereas their antifungal activity is significantly lower. The IC50 values for Hep G2 cells were within the range of 1.56-33.82 μmol/L, but there is no direct correlation with MICs for mycobacteria.