Synthesis, Kinetics and Computational Explorations of 4-Phenylpiperazine Bearing N-(Aryl)-3-substituted-benzamides as Auspicious Tyrosinase Inhibitors

In the aimed research study, a new series of N-(aryl)-3-[(4-phenyl-1-piperazinyl)methyl]benzamides was synthesized, which was envisaged as tyrosinase inhibitor. The structures of these newly designed molecules were verified by IR, 1H-NMR, 13C-NMR, EI-MS and CHN analysis data. These molecules were screened against tyrosinase and their inhibitory activity explored that these 3-substituted-benzamides exhibit good to excellent potential, comparative to the standard. The Kinetics mechanism was investigated through Lineweaver-Burk plots which depicted that molecules inhibited this enzyme in a competitive mode. Moreover, molecular docking was also performed to determine the binding interaction of all synthesized molecules (ligands) with the active site of tyrosinase enzyme and the results showed that most of the ligands exhibited efficient binding energy values. Therefore, it is anticipated that these molecules might serve as auspicious therapeutic scaffolds for treatment of the tyrosinase associated skin disorders.

Synthesis and Computational Exploration of Morpholine Bearing Halogenated Sulfonamides as Potential Tyrosinase Inhibitors

In the presented work, a new series of three different 4-((3,5-dichloro-2-[(2/4-halobenzyl)oxy]phenyl)sulfonyl)morpholines was synthesized and the structure of these compounds were corroborated by 1 H-NMR & 13 C-NMR studies. The in vitro results established all the three compounds as potent tyrosinase inhibitors relative to the standard. The Kinetics mechanism plots established that compound 8 inhibited the enzyme non-competitively. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0025 μM. Additionally, computational techniques were used to explore electronic structures of synthesized compounds. Fully optimized geometries were further docked with tyrosinase enzyme for inhibition studies. Reasonably good binding/interaction energies and intermolecular interactions were obtained. Finally, drug likeness was also predicted using the rule of five (RO5) and Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) characteristics. It is anticipated that current experimental and computational investigations will evoke the scientific interest of the research community for the above-entitled compounds.

Convergent synthesis, kinetics insight and allosteric computational ascriptions of thiazole-(5-aryl)oxadiazole hybrids embraced with propanamides as alkaline phosphatase inhibitors

Considering the varied pharmacological prominence of thiazole and oxadiazole heterocyclic moieties, a unique series of bi-heterocyclic hybrids, 8a-h, was synthesized in a convergent manner. The structures of newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, and IR spectral studies. The structure-activity relationship of these compounds was predicted by examining their inhibitory effects against alkaline phosphatase, whereby all these molecules exhibited superb inhibitory potentials relative to the standard used. The kinetics mechanism was determined by Lineweaver-Burk plots which revealed that 8g inhibited the studied enzyme non-competitively by forming an enzyme-inhibitor complex. The inhibition constant K_i calculated from Dixon plots for this compound was 0.42 μM. The allosteric computational study was coherent with the experimental records and these ligands exhibited good binding energy values (kcal mol^-1). The hemolytic analysis revealed their mild cytotoxicity towards red blood cell membranes and hence, these molecules have potential to be nontoxic medicinal scaffolds for the treatment of alkaline phosphate-associated ailments.

Modular and Computational Access to Innocuous Multistep Metal-Free Synthesis of 1,3,4-Oxadiazoles as Enzyme Inhibitors

An array of 1,3,4-oxadiazole hybrids, 7a-s, structurally intriguing cores with potential in natural product synthesis and drug discovery, have been synthesized using innovative comparable conventional and microwave-assisted protocols. The synthesis was performed by the reaction of secondary amine-based acetamides, 6a-s, as the electrophile and piperidine-based oxadiazoles as the nucleophile, 3, under the metal-free reaction conditions. High yield in minimum time with highest purity was obtained by the microwave-irradiated method instead of the conventional one. The structural elucidations were made through infrared, 1H NMR, 13C NMR, and elemental analysis studies. The whole array of synthesized compounds, 7a-s, was evaluated for their potential against α-glucosidase and butyryl cholinesterase (BChE) enzymes. Natural bond orbital and structural optimizations were made by using the B3LYP method and the basis set of 6-311++G(d,p). Frontier molecular orbitals and molecular electrostatic potential were calculated at the same level of selected compounds as potential candidates against BChE and α-glucosidase enzymes utilizing the time-dependent density functional theory. Fifteen compounds out of 19 were observed to be active against α-glucosidase enzyme in comparison with acarbose as the reference standard and 7 against the BChE enzyme compared to eserine as the reference standard. The highest potential of compound 7j against BChE is well correlated by the higher binding interaction with target protein as -10.2, calculated by docking studies. The recruited compounds against both enzymes could be the best anti-enzymatic drugs and part of drugs discovery programs after further analysis.

Synthesis of 2-[2,3-dihydro-1,4-benzodioxin-6-yl(phenylsulfonyl)amino]-N-(un/substituted-phenyl)acetamides as anti-diabetic agents

Purpose: To synthesize a series of new 2-[2,3-dihydro-1,4-benzodioxin-6-yl(phenylsulfonyl)amino]-N-(un/substituted-phenyl) acetamides, and evaluate their anti-diabetic potentials. Methods: Synthesis of the parent compound N-(2,3-dihydro-1,4-benzodioxin-6-yl) benzenesulfonamide (3) was carried out by reacting 2,3-dihydro-1,4-benzodioxin-6-amine (1) with benzenesulfonylchloride (2) in aqueous basic medium under definite pH controls. After that 3 was further treated with various 2-bromo-N-(un/substituted-phenyl)acetamides (6a-l) to yield new compounds (7a-l) in polar aprotic solvent, DMF (dimethylformamide), using LiH as activator. The proposed structures of the synthesized compounds were confirmed using proton-nuclear magnetic resonance (1H-NMR) and infra-red spectroscopy (IR), and CHN analysis. Their anti-diabetic potential was evaluated by α-glucosidase enzyme inhibitory studies. Results: All the new compounds demonstrated weak (7a-h, 7j and 7l) to moderate (7i and 7k) inhibitory activities against α-glucosidase enzyme. IC50 (50 % inhibition concentration) values for 7i and 7k were 86.31±0.11 μM and 81.12±0.13 μM, respectively relative to acarbose (reference standard) with IC50 of 37.38±0.12 μM. Conclusion: All the synthesized compounds have weak to moderate activity against α-glucosidase enzyme. These compounds can thus be considered as possible therapeutic entrants for type-2 diabetes.

2-Aminothiazole-Oxadiazole Bearing N-Arylated Butanamides: Convergent Synthesis, Tyrosinase Inhibition, Kinetics, Structure-Activity Relationship, and Binding Conformations

A multi-step synthesis of novel bi-heterocyclic N-arylated butanamides was consummated through a convergent strategy and the structures of these medicinal scaffolds, 7a-h, were corroborated using spectral techniques. The in vitro analysis of these hybrid molecules revealed their potent tyrosinase inhibition as compared to the standard used. The kinetics mechanism was investigated through Lineweaver-Burk plots which exposed that, 7f, inhibited tyrosinase enzyme non-competitively by forming the enzyme-inhibitor complex. The inhibition constants K_i calculated from Dixon plots for this compound was 0.025 μM. Their binding conformations were ascertained by in silico computational studies whereby these molecules disclosed good binding energy values (kcal/mol). So, it was anticipated from the current research that these bi-heterocyclic butanamides might be probed as imperative therapeutic agents for melanogenesis.

N-Sulfonated derivatives of (2-furoyl)piperazine: Promising antibacterial agents with mild cytotoxicity

2-Furoyl-1-piperazine (1) was treated with a series of alkyl/aryl sulfonyl chlorides (2a-i) under benignant conditions to obtain its N-sulfonated derivatives (3a-i). These compounds were screened for their antibacterial potential against pathogenic bacteria. The low Minimum Inhibitory Concentration (MIC) values of these molecules, in comparison of ciprofloxacin, demonstrated their high antibacterial potential. Cytotoxic activities were ascertained through their hemolytic potential and mild hemolytic profiles of these compounds proved them to be promising compounds for drug designing and development.

Synthesis of novel N-(2,3-dihydro-1,4-benzodioxin-6-yl)-2-{[5-(un/substituted-phenyl)-1,3,4-oxadiazol-2-yl]sulfanyl}acetamides as potent antibacterial agents

The synthetic methodology was initiated by reacting 1,4-benzodioxane-6-amine (1) with 2-bromoacetyl bromide (2) in aqueous alkaline media under dynamic pH control to get compound 2,3-dihydro-1,4-benzodioxin-6-yl-2-bromoacetamide (3). In the subsequent reactions, a variety of un/substituted-benzoic acids (4a-k), through a succession of three steps, was converted into respective oxadiazole nucleophiles, 7a-k. Finally, the targeted molecules, 8a-k, were obtained by reacting 7a-k with electrophile 3 in an aprotic polar solvent. These compounds were corroborated by spectral characterization like IR, EI-MS, 1H-NMR, and CHN analysis data. These molecules were screened for their antibacterial potential and most of them exhibited a potent activity. Moreover, their cytotoxicity was profiled through hemolytic activity and it was observed that majority of them was very modest in toxicity.

Synthesis and evaluation of novel 1, 2, 4-substituted triazoles for urease and anti-proliferative activity

1,2,4-triazoles are a major group of heterocyclic compounds. In the current work, a concise library of such triazoles synthesized through a multistep protocol. The synthesis involved hydrazinolysis of ethyl-2-(p-Cl-phenoxy) acetate followed by reflux with phenyl isothiocyanate to yield the intermediate 2-[2-(p-Cl-phenoxy)acetyl)-N-phenyl-hydrazinecarbothioamide. This intermediate was then cyclized to form 5-[p-(Cl-phenoxy)-methyl]-4-phenyl-4H-1,2,4-triazole-3-thiol (the parent moiety) at alkaline pH. In parallel, 3-bromopropionyl bromide was reacted with a series of phenylamines to yield N-(substituted-phenyl)bromopropanamides. In the final step, N-substitution of 5-[p-(Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-thiol was carried out with N-(substituted-phenyl)bromopropanamides to give desired library of 3-[5-[(p-Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-ylthio]-N-(substituted-phenyl) propan-amides (8a-l). The prepared moieties were identified via IR, NMR, & EIMS and evaluated for urease and anti-proliferative activities. 3-[5-[(p-Cl-phenoxy)-methyl]-4- phenyl-4H-1,2,4-triazole-3-ylthio]-N-(3-methyl-phenyl)propanamide 8k, was found to be most prominent hit as urease inhibitor (IC₅₀= 42.57± 0.13 µM) using thiourea as standard (IC₅₀= 21.25±0.15µM). The interaction of 8k with urease were studied using docking studies. Anti-proliferative activity results showed 8k as promising candidates and rest of the synthesized derivatives were found to be moderately anti-proliferative. Molecular docking results also displayed 8k, 8h, and 8c as potential hits for further study.

Synthesis, Kinetics, Binding Conformations and Structure-activity Relationship of Potent Tyrosinase Inhibitors: Aralkylated 2-aminothiazole-ethyltriazole Hybrids

Considering the diversified pharmacological importance of thiazole and triazole heterocyclic moieties, a unique series of S-aralkylated bi-heterocyclic hybrids, 7a-l, was synthesized in a convergent manner. The structures of newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, IR, and EI-MS spectral studies. The structure-activity relationship of these compounds was envisaged by analyzing their inhibitory effects against tyrosinase, whereby all these molecules exhibited potent inhibitory potentials relative to the standard used. The Kinetics mechanism was ascertained by Lineweaver-Burk plots, which revealed that 7g inhibited tyrosinase non-competitively by forming an enzyme-inhibitor complex. The inhibition constants K_i calculated from Dixon plots for this compound was 0.0057µM. These bi-heterocyclic molecules also disclosed good binding energy values (kcal /mol) when assessed computationally. So, these molecules can be considered promising medicinal scaffolds for the treatment of skin disorders.

REPORT - Synthesis of promising antibacterial and antifungal agents: 2-[[(4-Chlorophenyl)sulfonyl](2,3-dihydro-1,4-benzodioxin-6-yl)amino]-N-(un/substituted-phenyl)acetamides

In the presented work, 2,3-dihydro-1,4-benzodioxin-6-amine (1) was reacted with 4-chlorobenzenesulfonyl chloride (2) in presence of aqueous basic aqueous medium to obtain 4-chloro-N-(2,3-dihydro-1,4-benzodioxin-6-yl)benzenesulfonamide (3). In parallel, various un/substituted anilines (4a-l) were treated with bromoacetyl bromide (5) in basified aqueous medium to obtain corresponding 2-bromo-N-(un/substituted)phenylacetamides (6a-l) as electrophiles. Then the compound 3 was finally reacted with these electrophiles, 6a-l, in dimethylformamide (DMF) as solvent and lithium hydride as base and activator to synthesize a variety of 2-[[(4-chlorophenyl)sulfonyl](2,3-dihydro-1,4-benzodioxin-6-yl)amino]-N-(un/substituted)phenylacetamides (7a-l). The synthesized compounds were corroborated by IR, ¹H-NMR and EI-MS spectral data for structural confirmations. These molecules were then evaluated for their antimicrobial and antifungal activities along with their %age hemolytic activity. Some compounds were found to have suitable antibacterial and antifungal potential, especially the compound 2-[[(4-chlorophenyl)sulfonyl](2,3-dihydro-1,4-benzodioxin-6-yl)amino]-N-(3,5-dimethylphenyl)acetamide (7l) exhibited good antimicrobial potential with low value of % hemolytic activity.

Synthesis of some N-sulfonated derivatives of 1-[(E)-3-phenyl-2-propenyl]piperazine as suitable antibacterial agents

In the planned research work, the nucleophilic substitution reaction of 1-[(E)-3-phenyl-2-propenyl]piperazine (1) was carried out with different sulfonyl chlorides (2a-g) at pH 9-10 to synthesize its different N-sulfonated derivatives (3a-g). The structures of the synthesized compounds were characterized by their proton-nuclear magnetic resonance (¹H-NMR), carbon-nuclear magnetic resonance (¹³C-NMR) and Infra Red (IR) spectral data, along with CHN analysis. The inhibition potential of the synthesized molecules was ascertained against two bacterial pathogenic strains i.e. Bacillus subtilis and Escherichia coli. It was inferred from the results that some of the compounds were very suitable inhibitors of these bacterial strains. Moreover, their cytotoxicity was also profiled and it was outcome that most of these molecules possessed moderate cytotoxicity.

Report - Synthesis of new antibacterial agents encompassing tosyl, piperidine, propanamide and 1,3,4-oxadiazole functionalities

A series of propanamide compounds 6a-l was derived by N-substitution reactions, encompassing tosyl, piperidine and 1,3,4-oxadiazole moieties. The intended array of compounds 6a-l was afforded by a series of five steps reaction scheme. 1-Tosylpiperidin-4-carboxylate (1) was synthesized by the reaction of tosyl chloride (a) with ethyl isonipecotate (b) under mild basic conditions. Compound 1 was subjected to nucleophillic substitution by hydrazine to synthesize 1-tosylpiperidin-4-carbohydrazide (2). The compound, 5-(1-tosylpiperidin-4-yl)-1,3,4-oxadiazole-2-thiol (3) was synthesized by intermolecular cyclization of compound 2 by CS2 under strong basic conditions. The target compounds, 6a-l, were finally synthesized from 3 by reacting with different electrophiles, 5a-l, in an aprotic polar solvent with sodium hydride as an activator. The different propanamoyl electrophiles, 5a-l, were synthesized by the reaction of different aromatic and aliphatic amines, 4a-l, with 3-bromopropionyl chloride under mild basic conditions. The structural elucidation was carried out using modern spectroscopic techniques including IR, 1H-NMR and EI-MS. The antibacterial potential of synthesized compounds was assessed against five bacterial strains. Compounds 6a, 6c, 6d, 6e and 6f were found to be potent antibacterial agents.

Synthesis of Bi-heterocyclic Sulfonamides as Tyrosinase Inhibitors: Lineweaver-Burk Plot Evaluation and Computational Ascriptions

The designed bi-heterocyclic sulfonamides were synthesized through a two-step protocol and their structures were ascertained by spectral techniques including IR, 1H NMR and 13C NMR along with CHN analysis. The in vitro inhibitory effects of these sulfonamides were evaluated against tyrosinase and kinetics mechanism was analyzed by Lineweaver-Burk plots. The binding modes of these molecules were ascribed through molecular docking studies. These synthesized bi-heterocyclic molecules were identified as potent inhibitors relative to the standard (kojic acid) and compound 5 inhibited the tyrosinase non-competitively by forming an enzyme-inhibitor complex. The inhibition constant Ki (0.09 µM) for compound 5 was calculated from Dixon plots. Computational results also displayed that all compounds possessed good binding profile against tyrosinase and interacted with core residues of target protein.

Synthesis, Bacterial biofilm inhibition and cytotoxicity of new N-Alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides

The current research was commenced by reaction of 1,4-benzodioxane-6-amine (1) with 4-nitrobenzenesulfonyl chloride (2) in the presence of aqueous base under dynamic pH control at 9 to yield N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamide (3) which was further reacted with a series of alkyl/aralkyl halides (4a-i) in polar aprotic solvent using catalytic amount of lithium hydride which acts as base to afford some new N-alkyl/aralkyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-nitrobenzenesulfonamides (5a-i). The projected structures of all the synthesized derivatives were characterized by contemporary techniques i.e., IR, 1H-NMR and EIMS. The biofilm Inhibitory action of all synthesized molecules was carried out against Escherichia coli and Bacillus subtilis. It was inferred from their results that 5f and 5e exhibited suitable inhibitory action against the biofilms of these bacterial strains. Moreover, their cytotoxicity was also checked and it was concluded that these synthesized molecules displayed docile cytotoxicity.

BSA Binding, molecular docking and in vitro biological screening of some new 1, 2, 4-triazole heterocycles bearing azinane nucleus

A series of new compounds (5a-q), derived from 5-(1-(4-nitrophenylsulfonyl) piperidin-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiol (3) were proficiently synthesized to evaluate their biological activities. 1-(4-Nitrophenylsulfonyl) piperidine-4-carbohydrazide (2) was refluxed with phenylisothiocyanate to yield an adduct which was cyclized to compound 3 by reflux reaction with 10 % potassium hydroxide. The targeted compounds 5a-q, were synthesized by stirring alkyl/aralkyl halides (4a-q) and compound 3 in a polar aprotic solvent. 1H-NMR, ¹³C-NMR, EI-MS and IR spectral techniques were employed to confirm the structures of all the synthesized compounds. The compounds were biologically evaluated for BSA binding studies followed by anti-bacterial, anti-inflammatory and acetylcholinesterase (AChE) activities. The active sites responsible for the best AChE inhibition were identified through molecular docking studies. Compound 5e bearing 4-chlorobenzyl moiety found most active antibacterial and anti-inflammatory agent among the synthesized compounds. The whole library of synthesized compounds except compounds 5d and 5f was found highly active for AChE inhibition and recommended for in vivo studies so that their therapeutic applications may come in utilization.

Synthesis, molecular docking, dynamic simulations, kinetic mechanism, cytotoxicity evaluation of N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl} butanamides as tyrosinase and melanin inhibitors: In vitro, in vivo and in silico approaches

In the current research work, different N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides have been synthesized according to the protocol described in scheme 1. The synthesis was initiated by reacting various substituted anilines (1a-e) with 4-chlorobutanoyl chloride (2) in aqueous basic medium to give various electrophiles, 4-chloro-N-(substituted-phenyl)butanamides (3a-e). These electrophiles were then coupled with 1-[(E)-3-phenyl-2-propenyl]piperazine (4) in polar aprotic medium to attain the targeted N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides (5a-e). The structures of all derivatives were identified and characterized by proton-nuclear magnetic resonance (¹H NMR), carbon-nuclear magnetic resonance (¹³C NMR) and Infra-Red (IR) spectral data along with CHN analysis. The in vitro inhibitory potential of these butanamides was evaluated against Mushroom tyrosinase, whereby all compounds were found to be biologically active. Among them, 5b exhibited highest inhibitory potential with IC₅₀ value of 0.013 ± 0.001 µM. The same compound 5b was also assayed through in vivo approach, and it was explored that it significantly reduced the pigments in zebrafish. The in silico studies were also in agreement with aforesaid results. Moreover, these molecules were profiled for their cytotoxicity through hemolytic activity, and it was found that except 5e, all other compounds showed minimal toxicity. The compound 5a also exhibited comparable results. Hence, some of these compounds might be worthy candidates for the formulation and development of depigmentation drugs with minimum side effects.

Synthesis of new S-substituted derivatives of 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazol-2-ylhydrosulfide as suitable antibacterial and anticancer agents with moderate cytotoxicity

In the study presented here, the nucleophilic substitution reaction of 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazol-2-ylhydrosulfide was carried out with different alkyl/aralkyl halides (5a-r) to form its different S-substituted derivatives (6a-r), as depicted in scheme 1. The structural confirmation of all the synthesized compounds was done by IR, ¹H-NMR, ¹³C-NMR and CHN analysis data. Bacterial biofilm inhibitory activity of all the synthesized compounds was carried out against Bacillus subtilis and Escherichia coli. The anticancer activity of these molecules was ascertained using anti-proliferation (SRB) assay on HCT 116 Colon Cancer Cell lines while the cytotoxicity of these molecules was profiled for their haemolytic potential. From this investigation it was rational that most of the compounds exhibited suitable antibacterial and anticancer potential along with a temperate cytotoxicity.

α-Glucosidase inhibitory potential and hemolytic evaluation of newly synthesized 3,4,5-trisubstituted-1,2,4-triazole derivatives

A series of 1, 2, 4-triazole derivatives bearing piperidine moiety has been introduced as new anti-diabetic drug candidates with least cytotoxicity. p-Chlorophenylsulfonyl chloride (1) and ethyl nipecotate (2) were the starting reagents that resulted into corresponding 3,4,5-trisubstituted-1,2,4-triazole (6) through a series of steps. A series of electrophiles, 9a-e, were synthesized by reacting 4-bromobutyryl chloride (7) with differently substituted aromatic amines (8a-e) under basic aqueous medium. Target derivatives, 10a-e, were synthesized by the reaction of compound 6 with N-aryl-4-bromobutanamides (9a-e) in an aprotic solvent. Structures of all the derivatives were verified by spectroscopic analysis using IR, ¹H-NMR, ¹³C-NMR and EIMS. Most of the derivatives revealed moderate to good α-glucosidase inhibitory activity with reference to acarbose. The moderate hemolytic potential demonstrated least toxicity.

In vitro assessment of antibacterial, antifungal, enzyme inhibition and hemolytic activities of various fractions of Rhynchosia pseudo-cajan

The aims of the present investigation were to assess the antibacterial, antifungal, enzyme inhibition and hemolytic activities of various fractions of Rhynchosia pseudo-cajan Cambess. The methanolic extract of the plant was dissolved in the water (distilled) and then partitioned with the n-hexane, chloroform, EtOAc and n-BuOH sequentially. Antibacterial activity was checked against Escherichia coli, Pasturella multocida, Bacillus subtilis and Staphylococcus aureus by the disc diffusion method using streptomycin sulphate, a standard antibiotic, as positive control. Chloroform and ethyl acetate soluble fractions showed good activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. These fractions also showed good MIC values. The n-butanol soluble and remaining aqueous fraction also showed good activity against some strains. Antifungal activity was studied against four fungi i.e. Aspergillus niger, Aspergillus flavus, Ganoderma lucidum and Alternaria alternata by the disc diffusion method using fluconazole, a standard antifungal drug, as positive control. Chloroform, n-butanol and ethyl acetate soluble fraction showed good activity only against G. lucidum. Enzyme inhibition studies were done against four enzymes i.e. α-glucosidase, butyrylcholinesterase, acetyl cholinesterase and lipoxygenase. Aqueous fraction possessed very good activity against α-glucosidase, even greater than acarbose, a reference standard drug. Its IC50 value was found as 29.81±0.12 μg/ml as compared to acarbose having IC50 38.62±0.04 μg/ml. Chlroform and ethyl acetate soluble fractions also showed good activity against α-glucosidase. Ethyl acetate soluble and remaining aqueous fractions showed good activity against lipoxygenase. All the studied fractions showed very less toxicity i.e. <2.5%.

Synthesis of some new N-(alkyl/aralkyl)-N-(4-methoxyphenethyl) benzene sulfonamides as antibacterial agents against Escherichia

The present study comprises the synthesis of a new series of benzenesulfonamides derived from N-sulfonation of 2-(4-methoxyphenyl)-1-ethanamine (1). The synthesis was initiated by the reaction of 2-(4-methoxyphenyl)-1-ethanamine (1) with benzenesulfonyl chloride (2), to yield N-(4-methoxyphenethyl)benzenesulfonamide (3). This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides (4a-j) in N,N-dimethylformamide (DMF) and in the presence of a weak base lithium hydride (LiH) to obtain various N-(alkyl/aralkyl)-N-(4-methoxyphenethyl) benzenesulfonamides (5a-j). The characterization of these derivatives was carried out by spectroscopic techniques like IR, 1H-NMR, and 13C-NMR. Elemental analysis also supported this data. The biofilm inhibitory action of all the synthesized compounds was carried out on Escherichia coli and some of the compounds were identified to be very suitable inhibitors of this bacterial strain. Furthermore, the molecules were also tested for their cytotoxicity behavior to assess their utility as less cytotoxic therapeutic agents.

Designing of promising medicinal scaffolds for Alzheimer's disease through enzyme inhibition, lead optimization, molecular docking and dynamic simulation approaches

In the designed research work, a series of 2-furoyl piperazine based sulfonamide derivatives were synthesized as therapeutic agents to target the Alzheimer's disease. The structures of the newly synthesized compounds were characterized through spectral analysis and their inhibitory potential was evaluated against butyrylcholinesterase (BChE). The cytotoxicity of these sulfonamides was also ascertained through hemolysis of bovine red blood cells. Furthermore, compounds were inspected by Lipinki Rule and their binding profiles against BChE were discerned by molecular docking. The protein fluctuations in docking complexes were recognized by dynamic simulation. From our in vitro and in silico results 5c, 5j and 5k were identified as promising lead compounds for the treatment of targeted disease.

Synthesis, spectral analysis and biological evaluation of sulfamoyl and 1,3,4-oxadiazole derivatives of 3-pipecoline

Heterocyclic chemistry is an important field of organic chemistry due to therapeutic potential. The minor modification in the structure of poly-functional compounds has great effect on therapeutic ability. In the presented research work, substituted 1,3,4-oxadiazole derivatives, 8a-p, have been synthesized by the reaction of 1-(4-bromomethylbenzenesulfonyl)-3-methylpiperidine (7) and 5-substituted-1,3,4-oxadiazole-2-thiol (4a-p). The 5-substituted-1,3,4-oxadiazole-2-thiol were synthesized by converting carboxylic acids correspondingly into esters, hydrazides and oxadiazoles. Secondly the electrophile, 1-(4-Bromomethylbenzenesulfonyl)-3-methylpiperidine (7), was prepared by the reaction of 3-methylpiperidine with 4-bromomethylbenzenesulfonyl chloride in the presence of water and Na₂CO₃ under pH of 9-10. The compounds were structurally corroborated through spectroscopic data analysis of IR, EI-MS and 1H-NMR. The screening for antibacterial activity revealed the compounds to be moderate to excellent inhibitors against bacteria under study. Anti-enzymatic activity was assessed against urease enzyme and 1-{[4-({[5-(3-nitrophenyl)-1,3,4-oxadiazol-2-yl]sulfanyl}methyl)phenyl]sulfonyl}-3-methylpiperidine (8d) was the most active one.

Synthesis of some new N-(alkyl/aralkyl)-N-(2,3-dihydro-1,4-benzodioxan-6-yl)-4-chlorobenzenesulfonamides as possible therapeutic agents for Alzheimer's disease and Type-2 Diabetes

In the current research work, a series of new N-(alkyl/aralkyl)-N-(2,3-dihydro-1,4-benzodioxan-6-yl)-4-chlorobenzenesulfonamides has been synthesized by reacting 1,4-benzozzdioxan-6-amine (1) with 4-chlorobenzenesulfonyl chloride (2) to yield N-(2,3-dihydro-1,4-benzodioxan-6-yl)-4-chlorobenzenesulfonamide (3) which was further reacted with different alkyl/aralkyl halides (4a-n) to afford the target compounds (5a-n). Structures of the synthesized compounds were confirmed by IR, 1H-NMR, EI-MS spectral techniques and CHN analysis data. The results of enzyme inhibition showed that the molecules, N-2-phenethyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5j) and N-(1-butyl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5d), exhibited moderate inhibitory potential against acetylcholinesterase with IC50 values 26.25±0.11 μM and 58.13±0.15 μM respectively, whereas, compounds N-benzyl-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5i) and N-(pentane-2-yl)-N-(2,3-dihydro-1,4-benzodioxin-6-yl)-4-chlorobenzenesulfonamide (5f) showed moderate inhibition against α-glucosidase enzyme as evident from IC50 values 74.52±0.07 and 83.52±0.08 μM respectively, relative to standards Eserine having IC50 value of 0.04±0.0001 μM for cholinesterases and Acarbose having IC50 value 38.25±0.12 μM for α-glucosidase, respectively.

Synthesis of 2-Furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives as suitable antibacterial agents with mild cytotoxicity

The aim of the present research work was synthesis of some 2-furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives and to ascertain their antibacterial potential. The cytotoxicity of these molecules was also checked to find out their utility as possible therapeutic agents. The synthesis was initiated by reacting furyl(-1-piperazinyl)methanone (1) in N,N-dimethylformamide (DMF) and lithium hydride with different aralkyl halides (2a-j) to afford 2-furyl[(4-aralkyl)-1-piperazinyl]methanone derivatives (3a-j). The structural confirmation of all the synthesized compounds was done by IR, EI-MS, ¹H-NMR and ¹³C-NMR spectral techniques and through elemental analysis. The results of in vitro antibacterial activity of all the synthesized compounds were screened against Gram-negative (S. typhi, E. coli, P. aeruginosa) and Gram-positive (B. subtilis, S. aureus) bacteria and were found to be decent inhibitors. Amongst the synthesized molecules, 3e showed lowest minimum inhibitory concentration MIC = 7.52±0.μg/mL against S. Typhi, credibly due to the presence of 2-bromobenzyl group, relative to the reference standard, ciprofloxacin, having MIC = 7.45±0.58μg/mL.

In silico and BSA binding study of some new biological analogs of 1,2,4-triazolependant with azinane through microwave and conventional synthesis

Microwave and conventional techniques were employed to synthesize a novel array of compounds 7a-g with 1,2,4-triazole and piperidine rings having great biological importance. The microwave assisted method has a better operational scope with respect to time and yield comparative to the conventional method. 1H-NMR, 13C-NMR and IR techniques were employed to justify the structure of synthesized compounds. The antioxidant, butyrylcholinesterase inhibition and urease inhibition potential of every synthesized compound was evaluated. Every member of the synthesized series was found potent against mentioned activities. Compound 7g was the most active anti-urease agent having IC50 (μM) value 16.5±0.09 even better than the thiourea with an IC50(μM) value of 24.3±0.24. The better urease inhibition potential of 7g was also elaborated and explained by docking and bovine serum albumin (BSA) binding studies.

Synthesis, in vitro and in silico studies of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols as cholinesterase inhibitors

The research was aimed to unravel the enzymatic potential of sequentially transformed new triazoles by chemically converting 4-methoxybenzoic acid via Fischer's esterification to 4-methoxybenzoate which underwent hydrazinolysis and the corresponding hydrazide (1) was cyclized with phenyl isothiocyanate (2) via 2-(4-methoxybenzoyl)-N-phenylhydrazinecarbothioamide (3); an intermediate to 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazol-3-thiol (4). The electrophiles; alkyl halides 5(a-g) were further reacted with nucleophilic S-atom to attain a series of S-alkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols 6(a-g). Characterization of synthesized compounds was accomplished by contemporary spectral techniques such as FT-IR, 1H-NMR, 13C-NMR and EI-MS. Excellent cholinesterase inhibitory potential was portrayed by 3-(n-heptylthio)-5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole; 6g against AChE (IC50; 38.35±0.62μM) and BChE (IC50; 147.75±0.67μM) enzymes. Eserine (IC50; 0.04±0.01μM) was used as reference standard. Anti-proliferative activity results ascertained that derivative encompassing long straight chain substituted at S-atom of the moiety was the most potent with 4.96 % cell viability (6g) at 25μM and with 2.41% cell viability at 50μMamong library of synthesized derivatives. In silico analysis also substantiated the bioactivity statistics.

2-Furoic piperazide derivatives as promising drug candidates of type 2 diabetes and Alzheimer's diseases: In vitro and in silico studies

The heterocyclic compounds have been extensively reported for their bioactivity potential. The current research work reports the synthesis of some new multi-functional derivatives of 2-furoic piperazide (1; 1-(2-furoyl)piperazine). The synthesis was initiated by reacting the starting compound 1 with 3,5-dichloro-2-hydroxybenzenesulfonyl chloride (2) in a basic, polar and protic medium to obtain the parent sulfonamide 3 which was then treated with different electrophiles, 4a-g, in a polar and aprotic medium to acquire the designed molecules, 5a-g. These convergent derivatives were evaluated for their inhibitory potential against α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Acarbose was used as a reference standard for α-glucosidase inhibition while eserine for AChE and BChE inhibition. Some of the synthesized compounds were identified as promising inhibitors of these three enzymes and their bioactivity potentials were also supported by molecular docking study. The most active compounds among the synthetic analogues might be helpful in drug discovery and development for the treatment of type 2 diabetes and Alzhiemer's diseases.

Synthesis, spectral analysis and antibacterial activity of some novel 5-substituted-2-((6-bromo-3,4-methylenedioxybenzyl)thio)-1,3,4-oxadiazole derivatives

A number of novel 5-substituted-2-((6-bromo-3,4-methylenedioxybenzyl)thio)-1,3,4-Oxadiazole derivatives (6a-l) have been synthesized to evaluate their antibacterial activity. Using aryl/aralkyl carboxylic acids (1a-l) as precursors, 5-substituted-1,3,4-Oxadiazol-2-thiols (4a-l) were yielded in good amounts. The derivatives, 4a-l, were subjected to electrophilic substitution reaction on stirring with 6-bromo-3,4-methylenedioxybenzyl chloride (5) in DMF to synthesize the required compounds. All the synthesized molecules were well characterized by IR, ¹H-NMR, ¹³C-NMR and EIMS spectral data and evaluated for antibacterial activity against some bacterial strains of Gram-bacteria. The molecule, 6d, demonstrated the best activity among all the synthesized molecules exhibiting weak to moderate inhibition potential.

Conventional versus microwave assisted synthesis, molecular docking and enzyme inhibitory activities of new 3,4,5-trisubstituted-1,2,4-triazole analogues

N-(Substituted)-5-(1-(4-methoxyphenylsulfonyl)piperidin-4-yl)-4H-1,2,4-triazol-3-ylthio) acetamide were synthesized by following conventional as well as microwave assisted protocol through five consecutive steps under the impact of various reaction conditions to control the reaction time and the yield of product. Starting from 4-methoxybenzenesulfonyl chloride and ethyl isonipecotate, product 3 was obtained which was converted into product 4 by treating with hydrazine hydrate. In step 3, the product 4 was refluxed with methyl isothiocyanate and KOH to yield compound 5 which was finally treated with variety of N-substituted acetamides to yield an array of different new compounds (8a-k). These synthesized compounds were evaluated for their inhibition potential against bovine carbonic anhydrase (bCA-II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 8g demonstrated good activity against bCA-II, AChE and BChE with IC₅₀ values of 8.69 ± 0.38 μM, 11.87±0.19 μM and 26.01±0.55 μM respectively. SAR studies assisted with molecular docking were carried out to explore the mode of binding of the compounds against the studied enzymes.

Synthesis, enzyme inhibitory kinetics mechanism and computational study of N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides as novel therapeutic agents for Alzheimer's disease

The present study comprises the synthesis of a new series of sulfonamides derived from 4-methoxyphenethylamine (1). The synthesis was initiated by the reaction of 1 with 4-methylbenzenesulfonyl chloride (2) in aqueous sodium carbonate solution at pH 9 to yield N-(4-methoxyphenethyl)-4-methylbenzensulfonamide (3).This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides, (4a–j), using N,N-dimethylformamide (DMF) as solvent and LiH as activator to produce a series of new N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides (5a–j). The structural characterization of these derivatives was carried out by spectroscopic techniques like IR, ¹H-NMR, and ¹³C-NMR. The elemental analysis data was also coherent with spectral data of these molecules. The inhibitory effects on acetylcholinesterase and DPPH were evaluated and it was observed that N-(4-Methoxyphenethyl)-4-methyl-N-(2-propyl)benzensulfonamide (5c) showed acetylcholinesterase inhibitory activity 0.075 ± 0.001 (IC₅₀ 0.075 ± 0.001 µM) comparable to Neostigmine methylsulfate (IC₅₀ 2.038 ± 0.039 µM).The docking studies of synthesized ligands 5a–j were also carried out against acetylcholinesterase (PDBID 4PQE) to compare the binding affinities with IC₅₀ values. The kinetic mechanism analyzed by Lineweaver-Burk plots demonstrated that compound (5c) inhibits the acetylcholinesterase competitively to form an enzyme inhibitor complex. The inhibition constants Ki calculated from Dixon plots for compound (5c) is 2.5 µM. It was also found from kinetic analysis that derivative 5c irreversible enzyme inhibitor complex. It is proposed on the basis of our investigation that title compound 5c may serve as lead structure for the design of more potent acetylcholinesterase inhibitors.

Hypoglycemic, hepatoprotective and molecular docking studies of 5-[(4-chlorophenoxy) methyl]-1, 3, 4-oxadiazole-2-thiol

<p class="Abstract">The present study aimed at the evaluation of anti-hyperglycemic and hepatoprotective potential of a new drug candidate, 5-[(4-chlorophenoxy) methyl]-1,3,4-oxadiazole-2-thiol (OXCPM) through in vitro and in vivo assays, respectively. The compound displayed excellent dose-dependent ɑ-amylase (28.0-92.0%), ɑ-glucosidase (40.3-93.1%) and hemoglobin glycosylation (9.0%-54.9%) inhibitory effects and promoted the uptake of glucose by the yeast cells (0.2 to 26.3%). The treatment of the isoniazid- and rifampicin- (p.o., 50 mg/kg of each) intoxicated rats with OXCPM (100 mg/kg, p.o.) resulted in restoring the normal serum levels of the non-enzymatic (total bilirubin, total protein and albumin) and bringing about a remarkable decrease in the levels of enzymatic (alanine transaminases, aspartate transaminases and alkaline phosphatase) biomarkers. The molecular docking studies indicated high binding affinity of the compound for hyperglycemia-related protein targets; fructose-1,6-bisphosphatase, beta₂-adrenergic receptors and glucokinase. The results indicate that OXCPM may not only reduce hyperglycemia by enzyme inhibition but also the disease complications through protection of hemoglobin glycosylation and hepatic injury.</p><p class="Abstract"><strong>Video Clip of Methodology:</strong></p><p class="Abstract">Glucose uptake by yeast cells:   4 min 51 sec   <a href="https://www.youtube.com/v/8cJkuMtV0Wc">Full Screen</a>   <a href="https://www.youtube.com/watch?v=8cJkuMtV0Wc">Alternate</a></p>

Synthesis of some new 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides as potent antibacterial agents

In this work, a new series of 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides has been synthesized and evaluated for their antibacterial potential. The synthesis was initiated by the reaction of different aryl/aralkyl amines (1a-u) with 2-bromoacetylbromide (2) to obtain N-aryl/aralkyl-2-bromoacetamides (3a-u). Equimolar quantities of different N-aryl/aralkyl-2-bromoacetamides (3a-u) and 2-furoyl-1-piperazine (4) was allowed to react in acetonitrile and in the presence of K₂CO₃, to form 2-[4-(2-furoyl)-1-piperazinyl]-N-aryl/aralkyl acetamides (5a-u). The structural elucidation was done by EI-MS, IR and 1H-NMR techniques of all the synthesized compounds. All of the synthesized molecules were active against various Gram positive and Gram negative bacterial strains. Among them 5o and 5c showed very excellent MIC values. The cytotoxicity of the molecules was also checked to find their utility as possible therapeutic agents, where 5c (0.51%) and 5g (1.32%) are found to be least toxic in the series.

2-{[5-(Substituted-phenyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(1,3-thiazol-2-yl)acetamides: New bi-heterocycles as possible therapeutic agents

An electrophile, N-(1,3-thiazol-2-yl)-2-bromoacetamide (3), was synthesized by the reaction of 1,3-thiazole-2-amine (1) and 2-bromoethanoyl bromide (2) in an aqueous medium. A series of carboxylic acids, 7a-j, were converted into 1,3,4-oxadiazole heterocyclic core, through a series of three steps. The final compounds, 8a-j, were synthesized by stirring 7a-j and 3 in an aprotic polar solvent. The structural elucidation of the synthesized compounds was supported by IR, EI-MS, 1H-NMR, and ¹³C-NMR spectral data. Title compounds were evaluated for enzyme inhibition against cholinesterases and α-glucosidase enzymes and their cytotoxic behavior was monitored using brine shrimp assay. The enzyme inhibitor potential of compounds was supported by molecular docking studies.

Development and validation of a stability-indicating RP-HPLC-FLD method for determination of 5-[(4-chlorophenoxy) methyl]-1, 3, 4-oxadiazole-2-thiol; A novel drug candidate

The present study describes the development and validation of a simple high performance liquid chromatographic method for the determination of a novel drug candidate, 5-[(4-chlorophenoxy) methyl]-1, 3, 4-oxadiazole-2-thiol. The stability-indicating capacity of the method was evaluated by subjecting the compound's solution to hydrolytic, oxidative, photolytic, transition metal- and thermal- stress. The chromatographic separation was achieved over a C18 column (Promosil, 5 µm, 4.60 × 250 mm), maintained at 25°C, using an isocratic mobile phase comprising a mixture of acetonitrile and acidified water of pH 2.67 (1:1, v/v), at a flow rate of 1.00 mL/min and detection using a fluorescent light detector (excitation at 250 nm and emission at 410 nm). The Beer's law was followed over the concentration range 2.50-50.00 μg/ml. The recovery (98.56-100.19%, SD <5%), intraday accuracy and precision (97.31-100.81%, RSD <5%), inter-day accuracy and precision (97.50-100.75%, RSD <5%) and intermediate accuracy and precision (98.10-99.91%, RSD <5%) indicated that the method was reliable, repeatable, reproducible and rugged. The resolution and selectivity factors of the compound's peak from the nearest resolving peak, particularly in case of dry heat and copper metal stress, were found to be greater than 2 and 1, respectively, which indicated specificity and selectivity. The compound was extensively decomposed in alkaline-hydrolytic, oxidative, metal- and dry heat- stress. However, the compound in acidic and neutral conditions was resistant to photolysis. The results of the present study indicate that the developed method is specific, selective, sensitive and suitable, hence, may be used for quality control, stability testing and preformulation studies.

Novel indole based hybrid oxadiazole scaffolds with N-(substituted-phenyl)butanamides: synthesis, lineweaver–burk plot evaluation and binding analysis of potent urease inhibitors

In the study presented herein, 4-(1H-indol-3-yl)butanoic acid (1) was sequentially transformed in the first phase into ethyl 4-(1H-indol-3-yl)butanoate (2), 4-(1H-indol-3-yl)butanohydrazide (3) and 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazole-2-thiol (4) as a nucleophile. In the second phase, various electrophiles were synthesized by reacting substituted-anilines, 5a–j, with 4-chlorobutanoyl chloride (6) to afford 4-chloro-N-(substituted-phenyl)butanamides (7a–j). In the final phase, nucleophilic substitution reaction of 4 was carried out with different electrophiles, 7a–j, to achieve novel indole based oxadiazole scaffolds with N-(substituted-phenyl)butamides (8a–j). The structural confirmation of all the as-synthesized compounds was performed by spectral and elemental analysis. These molecules were screened for their in vitro inhibitory potential against urease enzyme and were found to be potent inhibitors. The results of enzyme inhibitory kinetics showed that compound 8c inhibited the enzyme competitively with a K_i value 0.003 μM. The results of the in silico study of these scaffolds were in full agreement with the experimental data and the ligands showed good binding energy values. The hemolytic study revealed their mild cytotoxicity towards cell membranes and hence, these molecules can be regarded as valuable therapeutic agents in drug designing programs.

In the study presented herein, 4-(1H-indol-3-yl)butanoic acid (1) was sequentially transformed in the first phase into ethyl 4-(1H-indol-3-yl)butanoate (2), 4-(1H-indol-3-yl)butanohydrazide (3) and 5-[3-(1H-indol-3-yl)propyl]-1,3,4-oxadiazole-2-thiol (4) as a nucleophile.