Facile synthesis of 1,3-thiazolidin-4-ones as antitubercular agents

Quantitative structure activity relationship (QSAR) modeling study of some novel thiazolidine 4-one derivatives as potent anti-tubercular agents

This study aims to develop a QSAR model for Antitubercular activity. The quantitative structure-activity relationship (QSAR) approach predicted the thiazolidine-4-ones derivative's Antitubercular activity. For the QSAR study, 53 molecules with Antitubercular activity on H37Rv were collected from the literature. Compound structures were drawn by ACD/Labs ChemSketch. The energy minimization of the 2D structure was done using the MM2 force field in Chem3D pro. PaDEL Descriptor software was used to construct the molecular descriptors. QSARINS software was used in this work to develop the 2D QSAR model. A series of thiazolidine 4-one with MIC data were taken from the literature to develop the QSAR model. These compounds were split into a training set (43 compounds) and a test set (10 compounds). The PaDEL software calculated 2300 descriptors for this series of thiazolidine 4-one derivatives. The best predictive Model 4, which has R2 of 0.9092, R2adj of 0.8950 and LOF parameter of 0.0289 identify a preferred fit. The QSAR study resulted in a stable, predictive, and robust model representing the original dataset. In the QSAR equation, the molecular descriptor of MLFER_S, GATSe2, Shal, and EstateVSA 6 positively correlated with Antitubercular activity. While the SpMAD_Dzs 6 is negatively correlated with Antitubercular activity. The high polarizability, Electronegativities, Surface area contributions and number of Halogen atoms in the thiazolidine 4-one derivatives will increase the Antitubercular activity.

One-Pot Synthesis of Novel 2-Imino-5-Arylidine-Thiazolidine Analogues and Evaluation of Their Anti-Proliferative Activity against MCF7 Breast Cancer Cell Line

An efficient surface-mediated synthetic method to facilitate access to a novel class of thiazolidines is described. The rationale behind the design of the targeted thiazolidines was to prepare stable thiazolidine analogues and evaluate their anti-proliferative activity against a breast cancer cell line (MCF7). Most of the synthesized analogues exhibited increased potency ranging from 2–15-fold higher compared to the standard reference, cisplatin. The most active thiazolidines contain a halogenated or electron withdrawing group attached to the N-phenyl ring of exocyclic 2-imino group. However, combination of the two substituents did not enhance the activity. The anti-proliferative activity was measured in terms of IC₅₀ values using an MTT assay.

Multicomponent reaction for the synthesis of new 1,3,4-thiadiazole-thiazolidine-4-one molecular hybrids as promising antidiabetic agents through α-glucosidase and α-amylase inhibition

A simple and efficient protocol was developed to synthesize a new library of thiazolidine-4-one molecular hybrids (4a-n) via a one-pot multicomponent reaction involving 5-substituted phenyl-1,3,4-thiadiazol-2-amines, substituted benzaldehydes and 2-mercaptoacetic acid. The synthesized compounds were evaluated in vitro for their antidiabetic activities through α-glucosidase and α-amylase inhibition as well as their antioxidant and antimicrobial potentials. Compound 4e exhibited the most promising α-glucosidase and α-amylase inhibition with an IC₅₀ value of 2.59 μM, which is ~1.5- and 14-fold superior as compared to the standard inhibitor acarbose. Structure-activity relationship (SAR) analysis revealed that the nature and position of substituents on the phenyl rings had a significant effect on the inhibitory potency.

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines

Two series of functionalized imidazothiazolotriazine derivatives were synthesized via the condensation of imidazo[4,5-e]-1,2,4-triazine-3-thiones with acetylenedicarboxylic acid dimethyl and diethyl esters (DMAD and DEAD) and subsequent base-catalyzed rearrangement of the obtained imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazines into regioisomeric imidazo[4,5-e]thiazolo[2,3-c]-1,2,4-triazine derivatives.

Antitubercular properties of thiazolidin-4-ones - A review

Thiazolidin-4-one scaffold has great potential for medicinal chemistry and is of interest to scientists in view of wide spectrum of biological activity. This scaffold is often used for designing of small molecules with various biological activity including antituberculosis activity. The presented review is an attempt to gather, analyze and systemize data about antitubercular properties of thiazolidine-4-ones from two last decades. Some of them have promising antitubercular activity which is significantly higher than that of the reference drugs. Among them compounds 82c, 82d and 84 that were active against M. tuberculosis H37Rv strain with MICs in the range of 0.05-0.2 μg/mL and compound 108 exhibited activity with MIC = 0.36 μM. Compounds 115a-115c and 116a-116c were very effective against M. tuberculosis H37Ra with MIC values in the range of 0.031-0.125 μg/mL. Acidomycin was showed activity against seven MDR M. tuberculosis strains with MICs in the range of 0.6-0.62 μM and against two XDR M. tuberculosis strains with MICs 0.096 and 1.2 μM. The structure-activity relationship (SAR) of some groups of compounds, as well as some potential molecular targets were also discussed.

Saturated Five-Membered Thiazolidines and Their Derivatives: From Synthesis to Biological Applications

In past decades, interdisciplinary research has been of great interest for scholars. Thiazolidine motifs behave as a bridge between organic synthesis and medicinal chemistry and compel researchers to explore new drug candidates. Thiazolidine motifs are very intriguing heterocyclic five-membered moieties present in diverse natural and bioactive compounds having sulfur at the first position and nitrogen at the third position. The presence of sulfur enhances their pharmacological properties, and, therefore, they are used as vehicles in the synthesis of valuable organic combinations. They show varied biological properties viz. anticancer, anticonvulsant, antimicrobial, anti-inflammatory, neuroprotective, antioxidant activity and so on. This diversity in the biological response makes it a highly prized moiety. Based on literature studies, various synthetic approaches like multicomponent reaction, click reaction, nano-catalysis and green chemistry have been employed to improve their selectivity, purity, product yield and pharmacokinetic activity. In this review article, we have summarized systematic approaches for the synthesis of thiazolidine and its derivatives, along with their pharmacological activity, including advantages of green synthesis, atom economy, cleaner reaction profile and catalyst recovery which will help scientists to probe and stimulate the study of these scaffolds.

Opportunities and challenges of using five-membered ring compounds as promising antitubercular agents

Tuberculosis (TB), a chronic infectious disease, is one of the greatest risks to human beings and 10 million people were diagnosed with TB and 1.6 million died from this disease in 2017. In addition, with the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), the TB situation has become even worse, which has aggravated the mortality and spread of this disease. To overcome this problem, research into novel antituberculosis agents with enhanced activities against MDR-TB, reduced toxicity, and shortened duration of therapy is of great importance. Fortunately, many novel potential anti-TB drug candidates with five-membered rings, which are most likely to be effective against sensitive and resistant strains, have recently entered clinical trials. Different five-membered rings such as furans, pyranoses, thiazoles, pyrazolines, imidazoles, oxazolidinone, thiazolidins, isoxazoles, triazoles, oxadiazoles, thiadiazoles, and tetrazoles have been designed, prepared, and evaluated for their antimycobacterial activity against Mycobacterium tuberculosis. In this article, we highlight the recent advances made in the discovery of novel five-membered ring compounds and focus on their antitubercular activities, toxicity, structure-activity relationships, and mechanisms of action.

An Insight of Alpha-amylase Inhibitors as a Valuable Tool in the Management of Type 2 Diabetes Mellitus

BACKGROUND

Among the millions of people around the world, the most prevalent metabolic disorder is diabetes mellitus. Due to the drawbacks which are associated with commercially available antidiabetic agents, new therapeutic approaches are needed to be considered. Alpha-amylase is a membrane- bound enzyme which is responsible for the breakdown of polysaccharides such as starch to monosaccharides which can be absorbed.

METHODS

We searched the scientific database using alpha-amylase, diabetes, antidiabetic agents as the keywords. Here in, only peer-reviewed research articles were collected which were useful to our current work.

RESULTS

To overcome the research gap, the alpha-amylase enzyme is regarded as a good target for antidiabetic agents to design the drug and provide an alternate approach for the treatment of type 2 diabetes mellitus. Basically, alpha-amylase inhibitors are classified into two groups: proteinaceous inhibitors, and non-proteinaceous inhibitors. Recently, non-proteinaceous inhibitors are being explored which includes chalcones, flavones, benzothiazoles, etc. as the potential antidiabetic agents.

CONCLUSION

Herein, we discuss various potential antidiabetic agents which are strategically targeted alpha-amylase enzyme. These are having lesser side effects as compared to other antidiabetic agents, and are proposed to prevent the digestion and absorption of glucose leading to a decrease in the blood glucose level.

Synthesis, in-Vitro Cytotoxicity and Antimicrobial Evaluations of Some Novel Thiazole Based Heterocycles

Condensation of rhodanine (1) with pyrazol-3(2H)-one derivatives (2a-f) gave 5-substituted-2-thioxo-1,3-thiazolidin-4-one derivatives (3a-f). Reaction of compound (1) with 2-arylmethylidene-malononitrile (4a-d) yielded the unexpected derivatives (5a-d). The latter compounds were subjected to cyclization reactions with malononitrile under different basic conditions, hydroxylamine hydrochloride and/or thiourea to furnish the fused thiazole derivatives (6a-d) and (8-10a-d). Coupling of (1) with diazotized aromatic amines (11a-c) in pyridine afforded the arylhydrazones (12a-c). Fusion of latter compounds with malononitrile afforded the thiazolopyridazine derivatives (13a-c). The structures of the newly synthesized compounds were elucidated via spectral data and elemental analyses. The in-vitro cytotoxic activity of compounds (3a-f) against the cell line MCF-7 was evaluated. Also, the synthesized products were investigated for their antibacterial and antifungal activities against six standard organisms including the G⁺ bacteria, Staphylococcus aureus and Bacillus subtilis, G^- bacteria, Escherichia coli and Proteus vulgaris in addition to fungi, Candida albicans and Aspergillus flavus.

Crosslinked sulfonated polyacrylamide (Cross-PAA-SO3H) tethered to nano-Fe3O4 as a superior catalyst for the synthesis of 1,3-thiazoles

Crosslinked sulfonated polyacrylamide (Cross-PAA-SO₃H) attached to nano-Fe₃O₄ as a superior catalyst has been used for the synthesis of 3-alkyl-4-phenyl-1,3-thiazole-2(3H)-thione derivatives through a three-component reactions of phenacyl bromide or 4-methoxyphenacyl bromide, carbon disulfide and primary amine under reflux condition in ethanol. A proper, atom-economical, straightforward one-pot multicomponent synthetic route for the synthesis of 1,3-thiazoles in good yields has been devised using crosslinked sulfonated polyacrylamide (Cross-PAA-SO₃H) tethered to nano-Fe₃O₄. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), dynamic light scattering (DLS), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA) and vibrating-sample magnetometer (VSM).

Copper-Catalyzed Electrophilic Ortho C(sp2)-H Amination of Aryl Amines: Dramatic Reactivity of Bicyclic System

A practical copper-catalyzed, 2-picolinamide-directed ortho C-H amination of anilines with benzoyl-protected hydroxylamines has been disclosed that proceeds smoothly without any external stoichiometric oxidant or additives. Remarkably, besides anilines, bicyclic naphthyl or heterocyclic amines furnished amination products with five- and six-membered cyclic and acyclic amines at the ortho position selectively. This electrophilic C-H amination also proceeds smoothly in water under slightly modified reaction conditions.

NewN-phenylacetamide-incorporated 1,2,3-triazoles: [Et3NH][OAc]-mediated efficient synthesis and biological evaluation

A facile, highly efficient, and greener method for the synthesis of new 1,4-disubstituted-1,2,3-triazoles was conducted using [Et₃NH][OAc] as a medium by the implementation of ultrasound irradiation via click chemistry, affording excellent yields. The present synthetic method exhibited numerous advantages such as mild reaction conditions, excellent product yields, minimal chemical waste, operational simplicity, shorter reaction time, and a wide range of substrate scope. The synthesized compounds were further evaluated for in vitro antifungal activity against five fungal strains, and some of the compounds displayed equivalent or greater potency than the standard drug. A molecular docking study against the modelled three-dimensional structure of cytochrome P450 lanosterol 14α-demethylase was also performed to understand the binding affinity and binding interactions of the enzyme. Furthermore, the synthesized compounds were evaluated for DPPH radical scavenging activity and antitubercular activity against Mycobacterium tuberculosis H37Rv strain.

A facile, highly efficient, and greener method for the synthesis of new 1,4-disubstituted-1,2,3-triazoles was conducted using [Et₃NH][OAc] as a medium by the implementation of ultrasound irradiation via click chemistry, affording excellent yields.

Uses of 2-(Thiophene-2-carbonylcarbamothioylthio)acetic Acid as a Good Synthon for Construction of Some New Thiazole and Annulated Thiazole Derivatives

The reaction of thiophene-2-carbonyl isothiocyanate 2 with thioglycolic acid gave 2-(thiophene-2-carbonylcarbamothioylthio)acetic acid 3. Compound 3 was subjected to some selected reactions with sulphuric acid as well as benzaldehyde, piperonal and isatin under different reaction conditions. The products obtained were new derivatives of thiazole and annulated thiazole derivatives bearing thiophene moiety in some cases. The structures of the new synthesized compounds were confirmed on the basis of their microanalytical and spectral properties. Some compounds were tested for their antimicrobial activity against six selected microorganisms using the standard antibacterial Gentamycin and antifungal Ketoconazole as references.

Triazole-diindolylmethane conjugates as new antitubercular agents: synthesis, bioevaluation, and molecular docking

We describe the synthesis of novel triazole-incorporated diindolylmethanes (DIMs) using a molecular hybridization approach. The in vitro antitubercular activity of the DIMs against Mycobacterium tuberculosis H37Ra (ATCC 25177) was tested in the active and dormant state. Among all the synthesized conjugates, the compounds 6b, 6f, 6l, 6n, 6q, 6r, and 6s displayed good antitubercular activity against both the active and dormant Mtb H37Ra strain. The compound 6l exhibited good antitubercular activity against dormant Mtb H37Ra with an IC₅₀ value of 1 μg mL^-1 and IC₉₀ (MIC) value of 3 μg mL^-1. The compounds 6b, 6l, and 6r displayed good antitubercular activity against active Mtb H37Ra with IC₅₀ values of 2.19, 1.52, and 0.22 μg mL^-1, respectively. The compounds 6b, 6h, 6l, and 6s displayed more than 70% inhibition against the Gram-positive Bacillus subtilus strain at 3 μg mL^-1. The molecular docking study showed the binding modes of the titled compounds in the active site of the DprE1 enzyme and assisted with elucidating a structural basis for the inhibition of Mycobacteria.

Ionic Liquid-Catalyzed Green Protocol for Multi-Component Synthesis of Dihydropyrano[2,3-c]pyrazoles as Potential Anticancer Scaffolds

A series of 6-amino-4-substituted-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles 5a-j were synthesized via one-pot, four-component condensation reactions of aryl aldehydes 1a-j, propanedinitrile (2), hydrazine hydrate (3) and ethyl acetoacetate (4) under solvent-free conditions. We report herein the use of the Brønsted acid ionic liquid (BAIL) triethylammonium hydrogen sulphate [Et₃NH][HSO₄] as catalyst for this multi-component synthesis. Compared with the available reaction methodology, this new method has consistent advantages, including excellent yields, a short reaction time, mild reaction conditions and catalyst reusability. Selected synthesized derivatives were evaluated for in vitro anticancer activity against four human cancer cell lines viz. melanoma cancer cell line (SK-MEL-2), breast cancer cell line(MDA-MB-231), leukemia cancer cell line (K-562) and cervical cancer cell line (HeLa). Compounds 5b, 5d, 5g, 5h and 5j exhibited promising anticancer activity against all selected human cancer cell lines, except HeLa. Molecular docking studies also confirmed 5b and 5d as good lead molecules. An in silico ADMET study of the synthesized anticancer agents indicated good oral drug-like behavior and non-toxic nature.

Synthesis of novel inhibitors of α-amylase based on the thiazolidine-4-one skeleton containing a pyrazole moiety and their configurational studies

Postprandial hyperglycemia can be controlled by delaying the absorption of glucose resulting from carbohydrate digestion. α-Amylase is the initiator of the hydrolysis of polysaccharides, and therefore developing α-amylase inhibitors can lead to development of new treatments for metabolic disorders like diabetes mellitus. In the present work, we set out to rationally develop α-amylase inhibitors based on the thiazolidine-4-one scaffold. The structures of all these newly synthesized hybrids were confirmed by spectroscopic analysis (IR, ¹H-NMR, MS). The appearance of two sets of signals for some protons in ¹H NMR revealed the existence of a mixture of 2E,5Z (37.1-42.0%) and 2Z,5Z isomers (58.4-62.8%), which was further supported by DFT studies. All the newly synthesized compounds have potential inhibitory properties as revealed through in vitro α-amylase inhibition activity. Compound 5a at 100 μg mL^-1 concentration showed a remarkable inhibition of 90.04%. In vitro α-amylase inhibition was further supported by docking studies of compound 5a against the active site of human pancreatic α-amylase (PDB ID: ; 2QV4). The docking studies revealed that the bonding interactions found between 5a and human pancreatic α-amylase are similar to those responsible for α-amylase inhibition by acarbose.

Novel tetrazoloquinoline-rhodanine conjugates: Highly efficient synthesis and biological evaluation

In search of new active molecules against Mycobacterium tuberculosis (MTB) H37Ra and Mycobacterium bovis BCG, a small focused library of rhodanine incorporated tetrazoloquinoline has been efficiently synthesized by using [HDBU][HSO4] acidic ionic liquid. The compound 3c found to be promising inhibitor of MTB H37Ra and M. bovis BCG characterized by lower MIC values 4.5 and 2.0 μg/mL, respectively. The active compounds were further tested for cytotoxicity against HeLa, THP-1, A549 and PANC-1 cell lines using MTT assay and showed no significant cytotoxic activity at the maximum concentration evaluated. Again, the synthesized compounds were found to have potential antifungal activity. Furthermore, to rationalize the observed biological activity data, the molecular docking study also been carried out against a potential target Zmp1 enzyme of MTB H37Ra, which revealed a significant correlation between the binding score and biological activity for these compounds. The results of in vitro and in silico study suggest that these compounds possess ideal structural requirement for the further development of novel therapeutic agents.

Novel tetrazoloquinoline–thiazolidinone conjugates as possible antitubercular agents: synthesis and molecular docking

Synthesis of new tetrazoloquinoline–thiazolidinone conjugates were achieved via one-pot three-component cyclocondensation in the presence of [DBUH][OAc] and studied antitubercular activity.