Efficient removal of toxic azo dyes from contaminated water by adsorption on the GO surface.

The purpose of this study is to examine the possibility of GO to be used as an adsorbent for five novel potentially hazardous azo-dyes for their removal from aqueous solution. Adsorption characteristics of GO for azo-dyes removal were investigated by means of experimental and computational DFT as well as Monte Carlo approaches. Experimental studies include the effect of adsorbent dose, contact time, and initial concentration, while computational investigation involves DFT and Monte Carlo (MC) simulations. Through DFT studies geometric, electronic, and thermodynamic parameters were explored and possible mechanism of interactions and adsorption energies by predicted through MC by searching lowest possible adsorption complexes. Experimental data were evaluated by Langmuir models in order to describe the equilibrium isotherms. Equilibrium data fitted well to the Langmuir model. Thermodynamic parameters i.e., free energy change, enthalpy change, and entropy change revealed that the removal of azo-dyes by adsorption on the surface of GO molecular sieves was spontaneous. Nature of the process was found to be physiosorption involving non-covalent interaction. The study unveiled that GO can be used as an efficient adsorbent material for the adsorption of azo-dyes from aqueous solution.

Design, Synthesis, QSAR studies, and Molecular Modeling of Some Novel Bis Methyl 2-[3-(benzo[d]thiazol-2-yl)-2-terephthaloyl-bis-4-oxo-thiazolidin-5-ylidene]acetates and Screening of their Antioxidant and Enzyme Inhibition Properties.

INTRODUCTION: Benzothiazolamine-based bisthiourea precursors were prepared in good yields. These bisthiourea derivatives were cyclized into symmetrical Bis Methyl 2-[3-(benzothiazol-2-yl)-2-terephthaloyl-bis-4-oxo-thiazolidin-5-ylidene]acetates, by their condensation with (DMAD) dimethyl but-2-meditate in the presence of dry methanol. METHOD: All these compounds were evaluated for their biological applications. Antioxidant activities were performed by adopting a DPPH radical assay, and an in vitro enzyme inhibition assay was performed to investigate their enzyme inhibitory potential against butyrylcholinesterase (BChE) and acetylcholinesterase (AChE). RESULT: Molecular modeling and QSAR studies were performed to monitor the binding propensity of imidathiazolidinone derivatives with enzymes and DNA. Also, electronic and steric descriptors were calculated to determine the effect of structure on the activity of imidathiazolidinone derivatives. CONCLUSION: The characterization of all the synthesized compounds was done by their physical data, FT-IR, NMR and elemental analysis.

Synthesis, Computational Studies, Antioxidant and Anti-Inflammatory Bio-Evaluation of 2,5-Disubstituted-1,3,4-Oxadiazole Derivatives.

The 1,3,4-oxadiazole derivatives Ox-6a-f have been synthesized by incorporating flurbiprofen moiety with the aim to explore the potential of target molecules to decrease the oxidative stress. The title compounds Ox-6a-f were prepared by simple reactions in which a flurbiprofen -COOH group was esterified with methanol in an acid-catalyzed medium, which was then reacted with hydrazine to afford the corresponding hydrazide. The acid hydrazide was then cyclized into 1,3,4-oxadiazole-2-thiol by reacting with CS2 in the presence of KOH. The title compounds Ox-6a-f were synthesized by the reaction of an -SH group with various alkyl/aryl chlorides, which involves an S-alkylation reaction. The structures of the synthesized Ox-6a-f derivatives were ascertained by spectroscopic data. The in silico molecular docking was performed against target proteins cyclooxygenase-2 COX-2 (PDBID 5KIR) and cyclooxygenase-1 COX-1 (PDBID 6Y3C) to determine the binding affinity of the synthesized compounds with these structures. It has been inferred that most of the synthesized compounds bind well with an active binding site of 5KIR compared to 6Y3C, and especially compound Ox-6f showed excellent binding affinity (7.70 kcal/mol) among all synthesized compounds Ox-6a-f. The molecular dynamic (MD) simulation has also been performed to check the stability of docking complexes of ligands with COX-2 by determining their root mean square deviation and root mean square fluctuation. Little fluctuation was observed in case of Ox-6f, which forms the most stable complex with COX-2. The comprehensive antioxidant potential of the synthesized compounds has been evaluated by determining their free radical scavenging activity, including DPPH, OH, nitric oxide (NO), and iron chelation assay. The derivative Ox-6f showed promising results with 80.23% radical scavenging potential at a dose of 100 µg/mL while ascorbic acid exhibited 87.72% inhibition at the same dose. The anti-inflammatory activity of the final products has also been performed, and inflammatory markers were assayed, such as a thiobarbituric acid-reducing substance, nitric oxide, interleukin-6 (IL-6), and COX-2. The derivatives Ox-6d and Ox-6f displayed higher anti-inflammatory activity, exhibiting 70.56% and 74.16% activity, respectively. The results were compared with standard ibuprofen, which showed 84.31% activity at the same dose, 200 µg/mL. The anti-inflammatory potential has been performed by following the carrageen-induced hind paw edema model, and results showed that derivative Ox-6f exhibited 79.83% reduction in edema volume compared to standard ibuprofen, which reduced 84.31% edema volume. As dry lab and wet lab results confirm each other, it has been deduced that derivative Ox-6f may serve as the lead structure to design potent compounds to address oxidative stress.

Synthesis, Carbonic Anhydrase II/IX/XII Inhibition, DFT, and Molecular Docking Studies of Hydrazide-Sulfonamide Hybrids of 4-Methylsalicyl- and Acyl-Substituted Hydrazide.

Carbonic anhydrases (CAs and EC 4.2.1.1) are the Zn2+ containing enzymes which catalyze the reversible hydration of CO2 to carbonate and proton. If they are not functioning properly, it would lead towards many diseases including tumor. Synthesis of hydrazide-sulfonamide hybrids (19-36) was carried out by the reaction of aryl (10-11) and acyl (12-13) hydrazides with substituted sulfonyl chloride (14-18). Final product formation was confirmed by FT-IR, NMR, and EI-MS. Density functional theory (DFT) calculations were performed on all the synthesized compounds to get the ground-state geometries and compute NMR properties. NMR computations were in excellent agreement with the experimental NMR data. All the synthesized hydrazide-sulfonamide hybrids were in vitro evaluated against CA II, CA IX, and CA XII isozymes for their carbonic anhydrase inhibition activities. Among the entire series, only compounds 22, 32, and 36 were highly selective inhibitors of hCA IX and did not inhibit hCA XII. To investigate the binding affinity of these compounds, molecular docking studies of compounds 32 and 36 were carried out against both hCA IX and hCA XII. By using BioSolveIT's SeeSAR software, further studies to provide visual clues to binding affinity indicate that the structural elements that are responsible for this were also studied. The binding of these compounds with hCA IX was highly favorable (as expected) and in agreement with the experimental data.

Molecular Docking, Synthesis, and Tyrosinase Inhibition Activity of Acetophenone Amide: Potential Inhibitor of Melanogenesis.

Tyrosinase and its related proteins are responsible for pigmentation disorders, and inhibiting tyrosinase is an established strategy to treat hyperpigmentation. The carbonyl scaffolds can be effective inhibitors of tyrosinase activity, and the fact that both benzoic and cinnamic acids are safe natural substances with such a scaffolded structure, it was speculated that hydroxyl-substituted benzoic and cinnamic acid derivatives may exhibit potent tyrosinase inhibitory activity. These moieties were incorporated into new chemotypes that displayed in vitro inhibitory effect against mushroom tyrosinase with a view to explore antimelanogenic ingredients. The most active compound, 2-((3-acetylphenyl)amino)-2-oxoethyl(E)-3-(2,4-dihydroxyphenyl)acrylate (5c), inhibited mushroom tyrosinase with an IC50 of 0.0020 ± 0.0002 µM, while 2-((3-acetylphenyl)amino)-2-oxoethyl 2,4-dihydroxybenzoate (3c) had an IC50 of 27.35 ± 3.6 µM in comparison to the positive control arbutin and kojic acid with a tyrosinase inhibitory activity of IC50 of 191.17 ± 5.5 µM and IC50 of 16.69 ± 2.8 µM, respectively. Analysis of enzyme kinetics revealed that 5c is a competitive and reversible inhibitor with dissociation constant (Ki) value 0.0072 µM. In silico docking studies with mushroom tyrosinase (PDB ID 2Y9X) predicted possible binding modes in the enzymatic pocket for these compounds. The orthohydroxyl of the cinnamic acid moiety of 5c is predicted to form hydrogen bond with the active site side chain carbonyl of Asn 260 (2.16 Å) closer to the catalytic site Cu ions. The acetyl carbonyl is picking up another hydrogen bond with Asn 81 (1.90 Å). The inhibitor 5c passed the panassay interference (PAINS) alerts. This study presents the potential of hydroxyl-substituted benzoic and cinnamic acids and could be beneficial for various cosmetic formulations.

Efficient Synthesis of Novel N-[4-Methyl-3-(4-(5-phenyl-1,3,4-oxadiazol-2- yl)phenyl)thiazol-2(3H)-ylidene]benzamide Hybrid Ring System as Potential Antibacterial Agents.

BACKGROUND: Heterocyclic compounds display versatile biological applications, so the aim of this paper was to prepare biologically important heterocycles with enhanced bacterial resistance and to evaluate for their various structural features that are responsible for their biological properties. OBJECTIVE: The objective was to synthesize bacterial resistance compounds with enhanced antibacterial properties. METHODS: Ester moiety containing thiazole ring was converted into its hydrazide derivatives. These heterocyclic derivatives were cyclized into another ring oxadiazole; hence a hybrid ring system of two biologically active rings was prepared. RESULTS: All the synthesized compounds were characterized by spectroscopic techniques and were screened for their antibacterial potential; they possess significant antibacterial activities. CONCLUSION: New hybrid heterocyclic ring systems were synthesized by cyclization of hydrazide derivatives by adopting two step strategy in good yields. All the synthesized compounds were evaluated for their antioxidant activities; they showed moderate to significant activities. QSAR and Molecular docking studies were performed to determine the mode of interaction. Experimental and computational data is in accordance with the determined antibacterial activities.

Methoxy-Substituted Tyramine Derivatives Synthesis, Computational Studies and Tyrosinase Inhibitory Kinetics.

Targeting tyrosinase for melanogenesis disorders is an established strategy. Hydroxyl-substituted benzoic and cinnamic acid scaffolds were incorporated into new chemotypes that displayed in vitro inhibitory effects against mushroom and human tyrosinase for the purpose of identifying anti-melanogenic ingredients. The most active compound 2-((4-methoxyphenethyl)amino)-2-oxoethyl (E)-3-(2,4-dihydroxyphenyl) acrylate (Ph9), inhibited mushroom tyrosinase with an IC50 of 0.059 nM, while 2-((4-methoxyphenethyl)amino)-2-oxoethyl cinnamate (Ph6) had an IC50 of 2.1 nM compared to the positive control, kojic acid IC50 16700 nM. Results of human tyrosinase inhibitory activity in A375 human melanoma cells showed that compound (Ph9) and Ph6 exhibited 94.6% and 92.2% inhibitory activity respectively while the positive control kojic acid showed 72.9% inhibition. Enzyme kinetics reflected a mixed type of inhibition for inhibitor Ph9 (Ki 0.093 nM) and non-competitive inhibition for Ph6 (Ki 2.3 nM) revealed from Lineweaver-Burk plots. In silico docking studies with mushroom tyrosinase (PDB ID:2Y9X) predicted possible binding modes in the catalytic site for these active compounds. Ph9 displayed no PAINS (pan-assay interference compounds) alerts. Our results showed that compound Ph9 is a potential candidate for further development of tyrosinase inhibitors.

Sulfonamide-Based Azaheterocyclic Schiff Base Derivatives as Potential Carbonic Anhydrase Inhibitors: Synthesis, Cytotoxicity, and Enzyme Inhibitory Kinetics.

A series of sulfonamide-bearing azaheterocyclic Schiff base derivatives 3(a-j) were synthesized as carbonic anhydrase inhibitors. The substituted benzene sulfonyl chlorides 1(a-d) were reacted with N2H4 to get aromatic sulfonyl hydrazides 2(a-d). The intermediate hydrazides 2(a-d) were treated with substituted aldehydes to afford azaheterocyclic sulfonamide Schiff bases 3(a-j). The spectral data of synthesized compounds confirmed the formation of the final products. The inhibitory effects of 3(a-j) on carbonic anhydrase activity were determined, and it was found that derivative 3c exhibited the most potent activity with IC500.84 ± 0.12 µM among all other derivatives and is also more active than standard acetazolamide (IC500.91 ± 0.12). The enzyme inhibitory kinetics results determined by Lineweaver-Burk plots revealed that compound 3c inhibits the enzyme by noncompetitive mode of inhibition with K i value 8.6 µM. The molecular docking investigations of the synthesized analogues 3(a-j) were evaluated which assured that synthesized compounds bind well inside the active binding site of the target enzyme. Cytotoxicity on human keratinocyte (HaCaT) and MCF-7 cell lines was performed, and it was found that most of the synthesized analogues were nontoxic on these cell lines and the toxic effects follow the dose-dependent manner. Based on our investigations, it was suggested that analogue 3c may serve as core structure to project carbonic anhydrase inhibitors with greater potency.

Enzyme Inhibitory Kinetics and Molecular Docking Studies of Halo-Substituted Mixed Ester/Amide-Based Derivatives as Jack Bean Urease Inhibitors.

A series of halo-substituted mixed ester/amide-based analogues 4a-l have been prepared as jack bean urease inhibitor, which showed good to excellent inhibition of enzyme activity. The role of halo-substituted benzoyl moieties and alkyl substituted anilines in urease inhibitory kinetics was also investigated. The alkyl-substituted anilines 1a-b reacted with chloroacetyl chloride to afford intermediates 2a-b, which were then reacted with different halo-substituted benzoic acids 3a-f to prepare the title compounds 4a-l. The chemical structures of final products 4a-l were ascertained by FTIR, 1H NMR, 13C NMR, and mass spectra. The compound 4b showed remarkable activity with IC501.6 ± 0.2 nM, better than the standard thiourea having IC50472.1 ± 135.1 nM. The 2-chloro-substituted phenyl ring on one side of compound 4b and 4-isopropyl-substituted benzene on the other side play an essential role in inhibition of urease activity. Lineweaver-Burk plots (kinetics study) indicated about 4b derivative as a mixed type of inhibitor. The virtual screening performed against urease enzyme (PDBID 4H9M) showed that compounds 4b and 4e have binding energies of -7.8 and -7.9 Kcal/mol, respectively. Based upon our results, it was found that derivative 4b is a highly potent urease inhibitor, better than the standard thiourea.

Synthesis, computational studies, tyrosinase inhibitory kinetics and antimelanogenic activity of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives.

The over expression of melanogenic enzymes like tyrosinase caused many hyperpigmentaion disorders. The present work describes the synthesis of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives 3a-e and 5a-e as antimelanogenic agents. The tyrosinase inhibitory activity of synthesized derivatives 3a-e and 5a-e was determined and it was found that derivative 5c possesses excellent activity with IC50 = 0.0089 µM compared to standard kojic acid (IC50 = 16.69 µM). The presence of hydroxyl groups at the ortho and the para position of cinnamic acid phenyl ring in compound 5c plays a vital role in tyrosinase inhibitory activity. The compound 5d also exhibited good activity (IC50 = 8.26 µM) compared to standard kojic acid. The enzyme inhibitory kinetics results showed that compound 5c is a competitive inhibitor while 5d is a mixed-type inhibitor. The mode of binding for compounds 5c and 5d with tyrosinase enzyme was also assessed and it was found that both derivatives irreversibly bind with target enzyme. The molecular docking and molecular dynamic simulation studies were also performed to find the position of attachment of synthesized compounds at tyrosinase enzyme (PDB ID 2Y9X). The results showed that all of the synthesized compounds bind well with the active binding sites and most potent derivative 5c formed stable complex with target protein. The cytotoxicity results showed that compound 5c is safe at a dose of 12 µg/mL against murine melanoma (B16F10) cells. The same dose of 5c was selected to determine antimelanogenic activity; the results showed that it produced antimelenogenic effects in murine melanoma (B16F10) cells. Based on our investigations, it was proposed that compound 5c may serve as a lead structure to design more potent antimelanogenic agents.

Investigation of potent inhibitors of cholinesterase based on thiourea and pyrazoline derivatives: Synthesis, inhibition assay and molecular modeling studies.

Owing to the desperate need of new drugs development to treat Alzheimer's ailment the synthesis of 1-aroyl-3-(5-(4-chlorophenyl)-1,2,4-triazole-3-thioneaminylthioureas (2-6) starting from (4-amino-5-(4-chlorophenyl)-4H-1,2,4-triazole-3-thiol) (1) and synthesis of 1-(3-(4-aminophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-2-(4-isobutylphenyl)propan-1-one (7-9) starting from 2-(4-isobutylphenyl)propanehydrazide (a) with the cyclization with substituted chalcones (c-e) was carried out. To check the biological potential of the synthesized compounds, all were subjected to acetylcholinesterase (AChE) and butrylcholinesterase (BChE) inhibition assays. The most potent and selective inhibitor for the acetylcholinesterase was compound 7 having an inhibitory concentration of 123 ±â€¯51 nM, whereas, compound 6 was found as selective inhibitor of butyrylcholinesterase (BChE) with an IC50 value of 201 ±â€¯80 nM. However, the compounds 1 and 2 were found as dual inhibitors i.e. active against both acetylcholinesterase as well as butyrylcholinesterase.

Dexibuprofen amide derivatives as potential anticancer agents: synthesis, in silico docking, bioevaluation, and molecular dynamic simulation.

BACKGROUND: The amide derivatives of nonsteroidal anti-inflammatory drugs have been reported to possess antitumor activity. The present work describes the synthesis of dexibuprofen amide analogues (4a-j) as potential anticancer agents. METHODS: The title amides (4a-j) were obtained by simple nucleophilic substitution reaction of dexibuprofen acid chloride with substituted amines in good yield and chemical structures were confirmed by FTIR, 1H NMR, 13C NMR and mass spectral data. RESULTS: The brine shrimp lethality assay results showed that all of the synthesized compounds are non-toxic to shrimp larvae. The inhibitory effects on tumor growth were evaluated and it was observed that N-(2,5-dichlorophenyl)-2-(4-isobutylphenyl) propionamide (4e) and N-(2-chlorophenyl)-2-(4-isobutylphenyl) propionamide (4g) exhibited excellent antitumor activity compared to all other derivatives. The compound 4e bearing 2,5-dichloro substituted phenyl ring and 4g possesses 2-chloro substituted phenyl ring exhibited 100% inhibition of the tumor growth. The anticancer activity was evaluated against breast carcinoma cell line (MCF-7) and it was observed that derivative 4e exhibited excellent growth inhibition of cancer cells with IC50 value of 0.01±0.002 µm, which is better than the standard drugs. The docking studies against breast cancer type 1 susceptibility protein BRCA1 (PDBID 3K0H) exhibited good binding affinities, which are in good agreement with the wet lab results. The compounds 4e and 4g showed the binding energy values of -6.39 and -6.34 Kcal/mol, respectively. The molecular dynamic (MD) simulation was also carried out to evaluate the residual flexibility of the best docking complexes of compounds 4e and 4g. The MD simulation analysis assured that the 4e formed a more stable complex with the target protein than the 4g. The synthesized amide derivatives exhibited were devoid of gastrointestinal side effects and no cytotoxic effects against human normal epithelial breast cell line (MCF-12A) were found. CONCLUSION: Based upon our wet lab and dry lab findings we propose that dexibuprofen analogue 4e may serve as a lead structure for the design of more potent anticancer drugs.

Synthesis, antimicrobial, antioxidant, cytotoxic, antiurease and molecular docking studies of N-(3-trifluoromethyl)benzoyl-N'-aryl thiourea derivatives.

An irrefutable advancement has been noted for the infectious diseases caused due to ureolytic bacteria through the development of various drugs. Keeping in mind the extremely valuable synthetic utility and medicinal significance of thiourea derivatives, synthesis of new 3-trifluoromethyl benzoic acid thiourea derivatives (3a-j) were carried out. The biological potential of all compounds in terms of antimicrobial, antioxidant, cytotoxic and antiurease activities were studied. The compounds 3a, 3c and 3i with dichloro and methoxy groups substitution on the aryl group showed significant activity against all strain of bacteria while moderate to no activity was observed in remaining compounds. Whereas the antifungal evaluation showed that all compounds were active againts C. Albican and no activity was observed against C. Prapsilosis. The cytotoxic findings revealed the non-toxic nature of these compounds as IC50 values of majority of the compounds are above 100 µm except for compounds 3f and 3g. In addition, these compounds exhibited better antioxidant potential as 100 µm concentration inhibited >50% reactive oxygen species (ROS) production except compounds 3e, 3f and 3j. The compound 3a proved to be the most potent urease inhibitor showing the highest enzyme % inhibition (93.1%) with IC50 value of 8.17 ±â€¯0.24 µM and found more active as compare to standard followed by compound 3e (92.6%), 3h (91.6%), 3d (90.8%), 3b (90.6%) and 3f (90.0%) with their respective IC50 values. All the synthesized compounds were docked into the binding cavity of Urease (PDB ID: 4ubp). The most active compound 3a was also ranked as top on the docking score as it was found to show valuable interactions with the target protein along with good docking scores. Hence our results revealed that the synthesized compounds have potential to be used as potent urease inhibitors after further detailed mechanistic studies.

Electrochemical, spectroscopic and theoretical monitoring of anthracyclines' interactions with DNA and ascorbic acid by adopting two routes: Cancer cell line studies.

Pharmacodynamic interactions of three anthracycline antibiotics namely doxorubicin (DXH), epirubicin (EpiDXH) and daunorubicin (DNR) with DNA in the absence and presence of ascorbic acid (AA) as natural additive were monitored under physiological conditions (pH = 7.4, 4.7 and T = 309.5K). Route-1 (Anthracycline-AA-DNA) and Route-2 (Anthracycline-DNA-AA) were adopted to see the interactional behavior by cyclic voltammetry (CV) and UV-visible spectroscopy. In comparison to Route-2; voltammetric and spectral responses as well as binding constant (Kb) and Gibb's free energy change (ΔG) values revealed strongest and more favorable interaction of anthracycline-AA complex with DNA via Route-1. Kb, s (binding site sizes) and ΔG evaluated from experimental (CV, UV-Vis) and theoretical (molecular docking) findings showed enhanced binding strength of tertiary complexes as compared to binary drug-DNA complexes. The results were found comparatively better at pH 7.4. Consistency was observed in binding parameters evaluated from experimental and theoretical techniques. Diffusion coefficients (Do) and heterogeneous electron transfer rate constant (ks,h) confirmed the formation of complexes via slow diffusion kinetics. Percent cell inhibition (%Cinh) of anthracyclines for non-small cell cancer cell lines (NSCCLs) H-1299 and H-157 were evaluated higher in the presence of AA which further complimented experimental and theoretical results.

Antihyperlipidemic studies of newly synthesized phenolic derivatives: in silico and in vivo approaches.

BACKGROUND: Hyperlipidemia is a worth-mentioning risk factor in quickly expanding cardiovascular diseases, including myocardial infarction and, furthermore, in stroke. METHODS: The present work describes the synthesis of phenolic derivatives 4a-e and 6a-c with the aim of developing antihyperlipidemic agents. The structures of the synthesized compounds were confirmed by spectroscopic data. The in silico docking studies were performed against human 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA) reductase enzyme (PDB ID: 1HWK), and it was observed that compounds 4a and 6a exhibited maximum binding affinity with target protein having binding energies -8.3 and -7.9 kcal, respectively. RESULTS: Compound 4a interacts with amino acids Val805 with distance 1.89 Å and Met656, Thr558, and Glu559 with bonding distances 2.96, 2.70, and 2.20 Å, respectively. The in vivo antihyperlipidemic activity results revealed that compound 4a indicated minimum weight increment, ie, 20% compared with 35% weight increment with standard drug atorvastatin during 6 weeks of treatment. Moreover, increment in high-density lipoprotein cholesterol and decrease in total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels were more prominent in case of 4a compared to atorvastatin with P<0.05. The synthesized compounds were nontoxic and well tolerated because none of the mice were found to suffer from any kind of morbidity and death during 6 weeks of dosing. CONCLUSION: Based on our pharmacological evaluation, we may propose that compound 4a may act as a lead structure for the design and development of more potent antihyperlipidemic drugs.

Synthesis, structure-activity relationship and molecular docking of 3-oxoaurones and 3-thioaurones as acetylcholinesterase and butyrylcholinesterase inhibitors.

The present study describes efficient and facile syntheses of varyingly substituted 3-thioaurones from the corresponding 3-oxoaurones using Lawesson's reagent and phosphorous pentasulfide. In comparison, the latter methodology was proved more convenient, giving higher yields and required short and simple methodology. The structures of synthetic compounds were unambiguously elucidated by IR, MS and NMR spectroscopy. All synthetic compounds were screened for their inhibitory potential against in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Molecular docking studies were also performed in order to examine their binding interactions with AChE and BChE human proteins. Both studies revealed that some of these compounds were found to be good inhibitors against AChE and BChE.

Design, synthesis, molecular docking studies and in vitro screening of ethyl 4-(3-benzoylthioureido) benzoates as urease inhibitors.

Thioureas are exceptionally versatile building blocks towards the synthesis of wide variety of heterocyclic systems, which also possess extensive range of pharmacological activities. The substituted benzoic acids were converted into corresponding acid chlorides, these acid chlorides were then treated with potassium thiocyanate in acetone and then the reaction mixture was refluxed for 1-2h afford ethyl 4-(3-benzoylthioureido)benzoates thioureas in good yields. All the newly synthesized compounds were evaluated for their urease inhibitory activities and were found to be potent inhibitors of urease enzyme. Compounds 1f and 1g were identified as the most potent urease inhibitors (IC50 0.21 and 0.13 µM, respectively), and was 100-fold more potent than the standard inhibitors. Further molecular docking studies were carried out using the crystal structure of urease to find out the binding mode of the inhibitors with the enzyme.

Total synthesis and antibacterial screening of ( ± )-7-butyl-6,8-dihydroxy-3-pentyl-3,4-dihydroisochromen-1-one.

A new total synthesis of ( ± )-7-butyl-6,8-dihydroxy-3-pentyl-3,4-dihydroisochromen-1-one, isolated as R-enantiomer from Geotrichum sp., has been described. Reaction of 4-butyl-3,5-dimethoxyhomophthalic anhydride with hexanoyl chloride in the presence of 1,1,3,3-tetramethyl guanidine and triethyl amine afforded 7-butyl-6,8-dimethoxy-3-pentylisochromen-1-one, which was converted into corresponding 3,4-dihydroisochromen-1-one by successive ring opening and reduction. Final demethylation to furnish the natural product was achieved using anhydrous aluminum chloride in ethanethiol. The target compound and the intermediates were subjected to antibacterial evaluation against 10 bacterial strains using levofloxacin as standard.

Synthesis and antibacterial evaluation of typharin analog: 6,8-dihydroxy-7-methyl-3-styryl-3,4-dihydroisocoumarin.

Synthesis of the 6-hydroxy-7-methyl analog of typharin (8-dihydroxy-3-styryl-3,4-dihydroisocoumarin) isolated from the rhizomes of Typha capensis has been described. Direct condensation of 3,5-dimethoxy-4-methylhomophthalic acid (1) with cinnamoyl chloride at elevated temperature under inert conditions afforded 6,8-dihydroxy-7-methyl-3-styrylisocoumarin (2). Hydrolysis of isocoumarin to keto acid (3) followed by reduction and cyclodehydration of hydroxy acid analog (4) afforded ( ± )-6,8-dimethoxy-3-(4-methoxyphenyl)-3,4-dihydroisocoumarin (5). Demethylation of the latter using anhydrous aluminum chloride/ethane thiol furnished the title isocoumarin (6). Compounds (1-6) were screened for in vitro antibacterial activity against a representative panel of Gram-positive and Gram-negative bacteria using levofloxacin as the reference drug.

6-Meth-oxy-1,3-benzothia-zol-2-amine.

The title compound, C(8)H(8)N(2)OS, is almost planar, the C-C-O-C torsion angle associated with the meth-oxy group being 0.72 (1)°. Inter-molecular amine N-H⋯N hydrogen-bonding inter-actions form inversion dimers [graph set R(2) (2)(8)] which are extended into chains along the b axis through amine N-H⋯O hydrogen bonds.