Rational drug design,synthesis,and biological evaluation of novel N-(2-arylaminophenyl)-2,3-diphenylquinoxaline-6-sulfonamides as potential antimalarial,antifungal,and antibacterial agents

Objective Sulfanilamide,sulfadiazine,and dapsone were the first sulfonamides to be used to treat malaria by disrupting the folate biosynthesis process,which is essential for parasite survival.Therefore,we aimed to synthesize novel N-(2-arylaminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide derivatives through a rational drug design approach.Methods All compounds were synthesized by the conventional method,and the products were characterized by spectral analysis(1 H NMR and mass spectrometry).The progression of the reaction was monitored using thin-layer chromatography(TLC).All the derivatives were analyzed for their effective binding mode in the allosteric site of the plasmodium cysteine protease falcipain-2.Antibacterial and antifungal activities were determined using the broth dilution method.Results S6(N-(2-thiazol-4 yl)-acetyl-aminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide and S9(N-(1 H-benzo[d]imidazol-2-yl)aminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide formed five hydrogen bonds;S8(N-(2-1 H-imidazol-2 yl)aminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide and S10(N-(1 H-benzo[d]imidazol-5-yl)aminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide formed four hydrogen bonds with the allosteric site of the enzyme.Considering the docking scores and formation of hydrogen bonds with the target enzyme,the novel derivatives were processed for wet lab synthesis.All the newly synthesized derivatives were subjected to in vitro antimalarial,antifungal,and antibacterial activities.All the derivatives exhibited sufficient sensitivity to the Plasmodium falciparum strain compared to the standards.Moreover,compounds S9 and S10 showed the most potent dual antimicrobial and antimalarial activities.They also exhibited powerful molecular interactions in molecular docking studies.Conclusion Based on the above results,it was concluded that N-(2-arylaminophenyl)-2,3-diphenylquinoxaline-6-sulfonamide derivatives have excellent biological potential to act as antimalarial,antifungal,and antibacterial agents.

Determination of fluoroquinolones, sulfonamides, and tetracyclines multiresidues simultaneously in porcine tissue by MSPD and HPLC-DAD

An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high performance liquid chromatography (HPLC) with diode array detection (DAD) is developed to effectively determine two fiuoroquinolones (enoxacin and lomefioxacin), two sulfonamides (sulfanilamide and sulfamethoxazole) and one tetracycline (tetracycline) simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v). Solvent acetonitrile and solvent acetic acid (0.1%) were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a fiow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 mg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs) (below 6.1%, nfi3) and the limits of quantitation (LOQ) ranged from 7 mg/kg to 34 mg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described.

Malaria parasite carbonic anhydrase:inhibition of aromatic/heterocyclic sulfonamides and its therapeutic potential

Plasmodium falciparum(P.falciparum) is responsible for the majority of life-threatening cases of human malaria,causing 1.5-2.7 million annual deaths.The global emergence of drug-resistant malaria parasites necessitates identification and characterisation of novel drug targets and their potential inhibitors.We identified the carbonic anhydrase(CA) genes in P.falciparum.The pfGA gene encodes an α-carbonic anhydrase,a Zn^(2+)-metalloenzme,possessing catalytic properties distinct from that of the human host CA enzyme.The amino acid sequence of the pfCA enzyme is different from the analogous protozoan and human enzymes.A library of aromatic/heterocyclic sulfonamides possessing a large diversity of scaffolds were found to be very good inhibitors for the malarial enzyme at moderate-low micromolar and submicromolar inhibitions.The structure of the groups substituting the aromatic-ureido-or aromatic-azomethine fragment of the molecule and the length of the parent sulfonamide were critical parameters for the inhibitory properties of the sulfonamides.One derivative,that is,4-(3,4-dichlorophenylureido)thioureidobcnzcnesulfonamide(compound 10) was the most effective in vitro Plasmodium falciparum CA inhibitor,and was also the most effective antimalarial compound on the in vitro P.falciparum growth inhibition.The compound 10 was also effective in vivo antimalarial agent in mice infected with Plasmodium berghei,an animal model of drug testing for human malaria infection. It is therefore concluded that the sulphonamide inhibitors targeting the parasite CA may have potential for the development of novel therapies against human malaria.

Survey of Tetracyclines, Sulfonamides, Sulfamethazine, and Quinolones in UHT Milk in China Market

This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.

Rapid analysis of fifteen sulfonamide residues in pork and fish samples by automated on-line solid phase extraction coupled to liquid chromatography–tandem mass spectrometry

The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.

Study on Pretreatment during Simultaneous Determination of Sulfonamides and Chloramphenicols in Honey

[ Objective] This study was conducted to establish a new UPLC-MS method for simultaneous detection of sulfonanfides and chloramphenicols in honey. [ Method] In this experiment, 0.2% formic acid-acetonitrile was used as an extractant to simultaneously extract chloramphenicoJs and sulfonamides from drugs. The extract was then loaded and extracted with an efficient separation column Oasis PRIME HLB. After nitrogen blow-concentration and dissolution with mobile phase, the extract was loaded on UPLC and detected by MS. [ Resultl There was a good linear relation in the range of 0. 1 - 10 ng/ml for chloramphenicols, with a correlation coefficient of 0.991, while sulfonamides had a good linear relation in the range of 0.5 - 50 ng/ml. The lowest detection limit of chloramphenicols and sulfonamides were 0. 1 and 0.5 μg/kg, respectively. The recoveries were in the range of 82.50% - 101.2%, with RSD values in the range of 3.2% -4.0%. [ Conclusion] This method is simple and fast with low detection limit, high recovery and good reproducibility, and could be used for simultaneous detection of re- sidual chloramphenicols and sulfonamides in honey. Key words UHPLC-MS; Sulfonamides ; Chloramphenicols ; Honey

GC-NICI-MS analysis of acetazolamide and other sulfonamide (R-SO2-NH2)drugs as pentafluorobenzyl derivatives [R-SO2-N(PFB)2] and quantification of pharmacological acetazolamide in human urine

Acetazolamide(molecular mass(MM),222)belongs to the class of sulfonamides(R-SO2-NH2)and is one of the strongest pharmacological inhibitors of carbonic anhydrase activity.Acetazolamide is excreted unchanged in the urine.Here,we report on the development,validation and biomedical application of a stable-isotope dilution GC-MS method for the reliable quantitative determination of acetazolamide in human urine.The method is based on evaporation to dryness of 50 mL urine aliquots,base-catalyzed derivatization of acetazolamide(d0-AZM)and its internal standard[acetylo-2H3]acetazolamide(d3-AZM)in 30 vol%pentafluorobenzyl(PFB)bromide in acetonitrile(60 min,30C),reconstitution in toluene(200 mL)and injection of 1-mL aliquots.The negative-ion chemical ionization(NICI)mass spectra(methane)of the PFB derivatives contained several intense ions including[M]‒at m/z 581 for d0-AZM and m/z 584 for d3-AZM,suggesting derivatization of their sulfonamide groups to form N,N-dipentafluorobenzyl derivatives(R-SO2-N(PFB)2),i.e.,d0-AZM-(PFB)2 and d3-AZM-(PFB)2,respectively.Quantification was performed by selected-ion monitoring of m/z 581 and 83 for d0-AZM-(PFB)2 and m/z 584 and 86 for d3-AZM-(PFB)2.The limits of detection and quantitation of the method were determined to be 300 fmol(67 pg)and 1 mM of acetazolamide,respectively.Intra-and inter-assay precision and accuracy for acetazolamide in human urine samples in pharmacologically relevant concentration ranges were determined to be 0.3%e4.2%and 95.3%e109%,respectively.The method was applied to measure urinary acetazolamide excretion after ingestion of a 250 mg acetazolamide-containing tablet(Acemit®)by a healthy volunteer.Among other tested sulfonamide drugs,methazolamide(MM,236)was also found to form a N,N-dipentafluorobenzyl derivative,whereas dorzolamide(MM,324)was hardly detectable.No GC-MS peaks were obtained from the PFB bromide derivatization of hydrochlorothiazide(MM,298),xipamide(MM,355),indapamide and metholazone(MM,366 each)or brinzolamide(MM,384).We demonstrate for the first time that sulfonamide drugs can be derivatized with PFB bromide and quantitated by GC-MS.Sulfonamides with MM larger than 236 are likely to be derivatized by PFB bromide but to lack thermal stability.

Synthesis and Characterization of 2-cetyl-3-20 keto acid(N-ethyl perfluorinated octyl sulfonamide) N-ethyl ester

2-Cetyl-3-20 keto acid（N-ethyl perfluorinated octyl sulfonamide） N-ethyl ester was synthesized by the reaction of N-ethyl-N-hydroxyethyl perfluorinated octyl sulfonamide and alky ketene dimer. The experimental results show that the yield of products can be 89% when the molar ratio of perfluorinated octyl sulfonamide to ketene dimer is 1 ： 1.1 and the reaction lasts about four hours at 80 ℃. The structure of the product was characterized by FTIR and ^1HNMR. The product can dissolve in polar solvents such as NMP, DMAC, THF, DMSO, CHCl3, and 10% weight-loss temperature measured by TGA is 202℃.

Study on Rapid Detection of Tetracyclines,Fluoroquinolones and Sulfonamides in Milk

Aiming at the market demand for rapid detection of tetracyclines,fluoroquinolones and sulfonamides in milk,a golloidal gold immunochromatography test strip for simultaneous detection of tetracyclines,fluoroquinolones and sulfonamides in milk was prepared based on the principle of competitive inhibition immunochromatography. The performance indicators of the test strip were verified. The results showed that the test strip can simultaneously detect 4 tetracyclines,13 fluoroquinolones and 13 sulfonamides,and the detection limits all can meet the national residue limits; the tests strip exhibited false positive rate≤5% and false negative rate = 0; and no cross-reaction with other drugs was commonly found in milk,indicating good specificity. The method is simple,rapid,and has low cost and easy popularization. It provides a means for realizing on-site rapid detection and is of important practical significance to guarantee of safety of milk and dairy products in China.

New Sulfonamides Derived from Carvacrol: Compounds with High Antibacterial Activity against Resistant Staphylococcus aureus Strains

Nine new sulfonamides derived from carvacrol were prepared through a reaction between 4-hydroxy-2-isopropyl-5-methyl benzene sulfonyl chloride with various amines in excellent yields (76% - 92%). The sulfonamides were characterized using spectrometric and spectroscopic methods. Among these compounds, three derivatives showed excellent results in antibacterial activity against resistant S. aureus strains, with MIC values ranging from 3.9 to 62.50 ppm. The sulfonamide derivative of 4-methylaniline (SULF-1) had the best performance for all tested strains of bacteria (MIC = 3.9 to 15.62 ppm). Furthermore, the sulfonamide derivative of 4-fluoro aniline (SULF-3), which also presented promising results, was found to have a synergistic effect when combined with tetracycline and partial synergistic effect when combined with ampicillin, exhibiting an FIC index between 0.50 and 0.75. The sulfonamide derivative of 4-methylaniline had a synergistic effect in combination with erythromycin exhibiting an FIC index of 0.37. Carvacrol in association with the antibiotics tested did not have a synergistic effect.

CATALYSIS OF POLYSTYRENE N-HYDROXYL SULFONAMIDE FOR ESTERIFICATION OF BUTANOL WITH ACETIC ANHYDRIDE

Polystyrene N-hydroxyl sulfonamide resin 1 was prepared and used to catalyze the esterification of n-butanol and acetic anhydride. The mechanism of catalytic esterification proved by IR spectra of the resins was found that O-H and N-H of the N-hydroxyl sulfonamide resin reacted with the acetic anhydride respectively to form the active intermediate polystyrene N,O-diacetyl sulfonamate which was cleaved by n-butanol to produce butyl acetate. The catalytic esterification by resin 1 was in good agreement with the kinetic model of 揵i-bi-ping-pong?mechanism.

Sulfonyl Imidazoles as Reagents for the Preparation of Sulfonates and Sulfonamides

Several new sulfonates and sulfonamides were synthesized with sulfonyl imidazoles as reagents. These compounds were characterized by ^1H NMR. The melting points of all solids synthesized were obtained on Fisher-Johns Melting Point Apparatus.

Petroleum exploitation enriches the sulfonamide resistance gene sul2 in off shore sediments

Antibiotic resistance genes(ARGs)have been considered as emerging contaminants in nature owing to their wide distribution and human health risk.Anthropogenic activities can increase the diversity and abundance of ARGs and promote their spread in environment.Offshore environment is affected by multiple types of anthropogenic activities,of which excessive accumulation of petroleum substances poses a serious threat.Our previous experimental study has demonstrated that petroleum can increase the abundance of sulfonamide resistance genes(SRGs)in the seawater through horizontal gene transfer.However,the influence of petroleum substances on SRGs in offshore environment,especially adjacent the petroleum exploitation platform,is still unclear.Therefore,the effect of offshore oil exploitation on SRGs was investigated in the surface sediments collected from the Liaodong Bay,north China.The genes of sul1 and sul2 were present in all of the collected samples,while the sul3 gene was not detected in any sediments.The absolute abundance of sul2 gene in each sample was higher than sul1 gene.Class 1 integrons enhanced the maintenance and propagation of sul1 gene but not sul2 gene.More importantly,the results indicate that the absolute abundance of sul2 gene present in the offshore sediments that affected by petroleum exploitation was significantly higher than those in control.These findings provided direct evidence that offshore oil exploitation can influence the propagation of SRGs and implied that a more comprehensive risk assessment of petroleum substances to public health risks should be conducted.

Simultaneous Prediction of Retention Times and Peak Shapes of Sulfonamides in Reversed-Phase High-Performance Liquid Chromatography

In this paper, we propose a novelmethod based on the plate theory to simultaneously predict retention times and peak shapes under gradient elutions and different flow rates by reversed-phase high-performance liquid chromatography. The proposed method yielded excellent retention prediction results in experiments with 16 common sulfonamides under 18 gradient conditions and four different flow rates, including 0.7, 1.0, 1.3, and 1.5 mL/min. The mean absolute deviation was 0.70%, which indicates accurate prediction. Moreover, the proposed method predicts the change wellin peak shapes caused by the expansion or compression ofpeaks under different gradient conditions.

Synthesis and Structure of bc-Dichloro-af-dihydroxo-de-bis(N-3-pyridinylmethanesulfonamide)platinum(Ⅳ) Diydrate

The Pt（IV） complex cis,cis,trans-[Pt（PMSA）2Cl2（OH）2]·2H2O（1）, where PMSA = N-3-pyridinylmethanesulfonamide, has been synthesized and characterized by elemental analysis, molar electric conductivity and IR spectrum. X-ray crystallography revealed that the title compound crystallizes in the monoclinic C2/c space group with unit cell dimensions a = 16.5424（7）, b = 8.6973（3）, c = 16.6079（6） A, β = 117.185（5）° and Z = 4. Pt（IV） has an octahedral coordination geometry and the PMSA ligands are coordinated via the pyridine N atom. They are in a transoid orientation between each other and are inclined in the same direction with respect to the Pt-C1-Cli-N-Ni plane at an angle of 64.6（1）° （symmetry operation： （i） 1- x, y, 3/2-z）. The structure is stabilized by a system of hydrogen bonds involving the complex and water molecules.

Crystal and Molecular Structure of N-(Pyridin-2-yl-carbonyl)-2-ethoxycarbonyl-benzene sulfonamide

The crystal and molecular structures of the title compound (C15H14N2O5S, Mr = 334.34) were determined by X-ray diffraction. The crystal structure is of triclinic, space group P with a = 7.306(1), b = 7.933(1), c =14.146(2) ?, a = 81.95, b = 80.28, g = 72.92? V = 768.9(2) 3, Z = 2, Dc = 1.444 g/cm3 , = 0.238mm-1, F(000) = 348, S = 1.033, the final R = 0.0453 and wR = 0.1181 for 2704 observed reflections with I >2s(I). In the molecule there are three different planes. In each of them a conjugated system is formed. The intra-molecular hydrogen bond between N and H atoms was ascertained and a five-membered ring including hydrogen bond is formed.

Investigation of Breaking Efficiency of N-Glycosidic Bond Between Sulfonamide and Honey

Sulfonamide residue in honey existed in a form bonded to sugar via the N-glycosidic bond.It would result in the possible underestimation of concentration of sulfonamide if it is not decomposed by chemical methods.However,in China's Mainland and Taiwan（P.R.China）,the regulation for sulfonamide residue analysis does not include hydrolysis and has been applied to a very broad range of samples,for example,egg,milk,meat,seafood as well as honey.This paper demonstrates the necessity of hydrolysis of it prior to extracting honey.The breaking efficiencies of N-glycosidic bond were investigated by 2 mol/L hydrochloric acid,pure methanol and 0.5 mol/L hydrochloric acid in methanol,respectively.It was found that acid plays the key role in breaking the N-glycosidic bond,and it was also noticed that the dissolution of liberated sulfonamide in methanol could carry the reaction forward in favor of breaking the N-glycosidic bond.

Asymmetric Transfer Hydrogenation of Ketone Catalyzed by Novel Ru(Ⅱ)-Chiral Sulfonamide Complex

Two new chiral Ru(Ⅱ)-sulfonamide complex have been used to catalyze the enantioselective transfer hydrogenation of prochiral ketones and the secondary alcohols are obtained with good to excellent optical yields.

Evaluation of the Antitumor and Radiosynthetizing Activity of a Novel Quinoline Sulfonamide Derivative (PIQSA) as a Histone Deacetylase Inhibitor

Inhibition of histone deacetylases (HDACs) is emerging as a new strategy in cancer therapy. In the present work a novel pyrimido-quinoline benzene sulfonamide (PIQSA compound) was designed and synthesized postulating its ability to inhibit HDAC enzyme in cancer cells. This study was designed to examine the in vitro anti-tumor efficacy of PIQSA against Ehrlich Ascite carcinoma cells (EAC) and three of the human cancer cell lines (H460), brain (U251) and liver (HepG2). The results of Cytotoxic assays showed that PIQSA exhibited in vitro antitumor activity in a dose dependant manner. The tumor growth delay studies indicating that PIQSA resulted in significant regression in tumor growth, which was more pronounced when PIQSA treatment accompanied with radiation exposure. Also, the efficacy of PIQSA to influence radiation response in Ehrlich solid carcinoma (ESC) tumors was estimated. The results suggest that PIQSA exhibited antitumor activities and strong radioenhancing properties associated with inhibition of HDAC activity, DNA fragmentation followed by apoptotic cell death, preferential cell loss of cells particularly in G1/G0 phase through an apoptotic pathway.

Design, Synthesis and Characterization of Novel Sulfonamides Derivatives as Anticancer Agent Targeting EGFR TK, and Development of New Methods of Synthesis by Microwave Irradiation

Some novel sulfonamide-derivatives were designed to develop novel kinase inhibitors. The molecular docking study was performed for the designed compounds against epidermal growth factor kinase receptor T790M/L858R (TMLR) (PDB ID: 5EDQ) to identify new drug candidates for treating cancer. Binding free energy was calculated by Molegro virtual docker (MVD) to select the most promising hits. The corresponding docking score values into EGFR (TMLR) of 4b gave the best energy docking -147.213 Kcal/mol. And some of the designed sulfonamide derivatives have been synthesized by conventional method in addition to a microwave-assisted method of synthesis. The reaction of an amino group-containing drug;sulfamethoxazole and sulfanilamide with carbonyl group in benzoyl chloride and phthalic acid in basic media, generated a series of sulfonamide derivatives. The structures of all the synthesized compounds were well characterized by Mass spectrometry (MS), Infrared spectroscopy (IR), 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance (13C NMR) and elemental analysis. After obtaining experimental data regarding the yield and the time taken for the synthesis by both the approaches, conventional and microwave-assisted method, it was shown that the microwave-assisted method gave higher yield with shorter time and higher temperature compared to conventional heating methods.