Synthetic Utility of Ethylidenethiosemicarbazide: Synthesis and Anticancer Activity of 1,3-Thiazines and Thiazoles with Imidazole Moiety

Exploring the Diverse Therapeutic Applications of 1, 3-Thiazine: A Comprehensive Review

Thiazine, a six-membered heterocycle containing nitrogen and sulfur atoms, is of paramount importance due to its diverse biological functions and broad therapeutic effects. The pharmacological attributes of 1,3-thiazine span a wide range of activities, including antileukemic, antimycobacterial, anti-inflammatory, sedative, hypnotic, anti-influenza, antituberculosis, melanogenesis inhibition, BACE1 inhibition (with anti-Alzheimer's potential), growth promotion, neuroprotective, and anticonvulsant properties. Consequently, novel synthetic methodologies and the design of new 1,3-thiazine derivatives are significantly influenced by recent research findings. This comprehensive review explores both in vivo and in vitro preclinical studies on the biomedical and therapeutic applications of 1,3-thiazine, highlighting its extensive medical relevance. It is anticipated that derivatization strategies for 1,3-thiazine will open new avenues for the development of innovative biological agents. This review aims to engage researchers, stimulating the creation of promising new treatments and preventive measures for various diseases.

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.

Novel Imidazole Liquid Crystals; Experimental and Computational Approaches

The liquid crystalline materials named (E)-4-(2-(4-oxo-5,5-diphenyl-4,5-dihydro-1H-imidazol-2-yl)hydrazineylidene)methyl)phenyl and 4-(alkoxy)benzoate, In, were synthesized and their mesomorphic behaviors were examined. The chemical structures of the produced compounds were confirmed by Fourier-transform infrared spectroscopy (FT-IR), NMR, and elemental analysis. Differential scanning calorimetry (DSC) and polarized optical microscopy were used to investigate the mesomorphic properties of designed heterocyclic derivatives. All the compounds tested had suitable thermal stability and enantiotropic behavior of smectogenic temperature ranges. Furthermore, the enantiotropic smectic C phases were observed to cover all the homologues. Moreover, computational investigations corroborated the experimental findings of the mesomorphic behavior. The reactivity parameters were computed for the derivatives and linked with the experimental data. Theoretical calculations revealed that the polarizability of the studied series increases with the chain length, whereas the HOMO–LUMO energy gap or other reactivity descriptors were less sensitive to the size of the system. On the other hand, the predicted thermodynamic parameters revealed the size dependence of thermal stability of the compounds.

Pharmacological Evaluation of Novel 1,2,4-triazine Derivatives Containing Thiazole Ring against Hepatocellular Carcinoma

Background:

New 6-hydroxy-5-(p-hydroxybenzylidene)-3-phenyl-2- [(5-pchlorophenyl)- 1,3-thiazol-2-yl]-1, 2, 4-triazine derivatives containing a thiazole ring were synthesised as potential antitumor agents.

Methods:

Cytotoxicity of compounds (3) and (4) was evaluated in human hepatocellular carcinoma (HCC) cell lines (HepG2); compound (3) showed more cytotoxicity (IC50=9.0μg/ml) than compound (4) (IC50=18.40μg/ml) using doxorubicin as standard. The degree of toxicity of compound (3) was assessed by the LD50 with its anticancer performance by suppressing tumor angiogenesis against diethylnitrosamine (DENA) induced hepatocellular carcinoma (HCC) in male rat model.

Results :

Carcinogenic rats showed a significant increase in markers of angiogenesis, tumour growth, and liver function tests and malondialdehyde level coupled with reduced hepatic glutathione level and caspase-3 activity. The distribution of compound (3) to animals after the development of HCC improved biochemical alterations from a DENA chemical carcinogen that is confirmed by hepatic histopathology.

Conclusion:

Compound 3 perhaps utilized as a strong applicant for newly therapeutic protocols against hepatocarcinogenesis by controlling tumor angiogenesis and renovating the activity of hepatic marker enzymes in addition to reversing the oxidant-antioxidant imbalance in corporation with amelioration of histopathology. While the trial supports the use of compound 3 for improved HCC outcome and the toxicity and side effects should be considered.

Synthesis and Biological Evaluation of Thiazolyl-Ethylidene Hydrazino-Thiazole Derivatives: A Novel Heterocyclic System

The reaction of 2-(1-(2-(2-(4-methoxybenzylidene)hydrazinyl)-4-methylthiazol-5-yl)ethylidene)hydrazinecarbothioamide with a range of hydrazonoyl chlorides and α-halo-compounds yielded three new series of thiazole derivatives. Chemical and physical techniques were used to analyze all newly prepared derivatives (1H-NMR, 13C-NMR, FT-IR and mass spectrometry). The potential antimicrobial and anticancer properties of the synthesized derivatives were investigated using various in vitro biological experiments. Most of the thiazole compounds tested were effective against Gram-positive and Gram-negative bacteria. In addition, a minimum inhibition concentration was determined for the antibiotic properties of the most active produced substances. The cytotoxic activities were tested on HepG-2 (liver carcinoma), HCT-116 (colorectal carcinoma) and MDA-MB-231 (breast carcinoma) cell lines in comparison with cisplatin reference drug and using colorimetric MTT assay. The results detected that compound 10c was the most potent against the three tested cell lines. Interestingly, when the tested compounds were evaluated for their toxicity against normal (MRC-5) cells, they exhibited low toxic effects indicating the safe use of most of them that may require further in vivo and pharmacological studies.

Microwave-Assisted One Pot Three-Component Synthesis of Novel Bioactive Thiazolyl-Pyridazinediones as Potential Antimicrobial Agents against Antibiotic-Resistant Bacteria

Pyridazine and thiazole derivatives have various biological activities such as antimicrobial, analgesic, anticancer, anticonvulsant, antitubercular and other anticipated biological properties. Chitosan can be used as heterogeneous phase transfer basic biocatalyst in heterocyclic syntheses. Novel 1-thiazolyl-pyridazinedione derivatives were prepared via multicomponent synthesis under microwave irradiation as ecofriendly energy source and using the eco-friendly naturally occurring chitosan basic catalyst with high/efficient yields and short reaction time. All the prepared compounds were fully characterized by spectroscopic methods, and their in vitro biological activities were investigated. The obtained results were compared with those of standard antibacterial/antifungal agents. DFT calculations and molecular docking studies were used to investigate the electronic properties and molecular interactions with specific microbial receptors.

Heterocycle Compounds with Antimicrobial Activity

Background:

Bacterial infections are a growing problem worldwide causing morbidity and mortality mainly in developing countries. Moreover, the increased number of microorganisms, developing multiple resistances to known drugs, due to abuse of antibiotics, is another serious problem. This problem becomes more serious for immunocompromised patients and those who are often disposed to opportunistic fungal infections.

Objective:

The objective of this manuscript is to give an overview of new findings in the field of antimicrobial agents among five-membered heterocyclic compounds. These heterocyclic compounds especially five-membered attracted the interest of the scientific community not only for their occurrence in nature but also due to their wide range of biological activities.

Method:

To reach our goal, a literature survey that covers the last decade was performed.

Results:

As a result, recent data on the biological activity of thiazole, thiazolidinone, benzothiazole and thiadiazole derivatives are mentioned.

Conclusion:

It should be mentioned that despite the progress in the development of new antimicrobial agents, there is still room for new findings. Thus, research still continues.

Discovery of thiazole-based-chalcones and 4-hetarylthiazoles as potent anticancer agents: Synthesis, docking study and anticancer activity

The crucial need for novel antitumor agents with high selectivity toward cancer cells has promoted us to synthesize new series of thiazole-based chalcones and 4-hetarylthiazoles (rigid chalcones). The synthesis of thiazolyl chalcones and 4-hetarylthiazoles and the assertion of their structure are described. Their anti-proliferative activity was estimated against three human cancer cell lines; HepG-2, A549 and MCF-7. 3-(4-Methoxyphenyl)-1-(5-methyl-2-(methylamino)thiazol-4-yl)prop-2-en-1-one (chalcone derivative 3a) showed significant and broad antitumor activity that was more potent than Doxorubicin. In addition, compounds 3d, 3e and 7a displayed potent activity compared to Doxorubicin. Additionally, these compounds were less toxic on normal lung cells WI-38 with high selectivity index. Further study on 3a regarding its effect on the normal cell cycle profile in A549 cells demonstrated cell cycle arrest at the G2/M phase together with rise in the percentage of the apoptotic pre-G1 cells. CDK1/CDK2/CDK4 inhibition assays were carried out on 3a, 3d, 3e and 7a and the results revealed non selective inhibition on the tested CDKs with IC₅₀ values of 0.78-1.97 µM. Moreover, docking study predicted that 3a, 3d, 3e and 7a can fit in the ATP binding site of CDK1 enzyme. The apoptosis induction potential of 3a, 3d, 3e and 7a was also estimated against some apoptosis markers. Interestingly, they elevated the level of Bax by 6.36-10.12 folds and reduced the expression of Bcl-2 by 1.94-4.12 folds compared to the control. Furthermore, they increased both active caspase-3 and p53 levels by 8.76-10.56 and 6.85-10.36 folds, respectively higher than the control which indicates their potential to induce apoptosis.

One-Pot Three-Component Synthesis and Molecular Docking of Some Novel 2-Thiazolyl Pyridines as Potent Antimicrobial Agents

BACKGROUND

Thiazoles and pyridines are versatile synthetic scaffolds possessing wide spectrum of biological effects including potential antimicrobial activity.

OBJECTIVE

In the efforts to develop suitable antimicrobia drugs, medicinal chemists have focused on thiazole derivatives. A novel series of 2-thiazolyl pyridines was prepared in a one-pot three-component reaction using 2-bromoacetyl pyridine as a starting precursor.

METHOD

Structure of the synthesized compounds was elucidated by spectral data (FT-IR, 1H NMR, 13C NMR, and mass) and elemental analyses. The prepared compounds were screened for their in vitro antimicrobial activity.

RESULTS

The results revealed that compounds 4a,b,e-g and 12 showed promising activity. Molecular docking studies using MOE software were carried out for compounds 4a and 4b which exhibited potent activities indicated by the diameter zones (4a; 3.6, 4.0, 1.2 mm) (4b; 4.2, 3.5, 1.5 mm) and the binding affinities (4a; -5.7731, -5.3576, -4.6844 kcal mol-1) (4b; -5.9356, -2.8250, -5.3628 kcal mol-1) against Candida albicans, Bacillus subtilis and Escherichia coli, respectively.

CONCLUSION

This paper describes a facile and efficient MCR for synthesis of 2-thiazolyl pyridines from reaction of 2-bromoacetyl pyridine with different reagents. There was an agreement between the values of binding affinities and interactions and the data obtained from the practical antimicrobial screening of the tested compounds.

Synthesis and Biological Evaluation of Some Novel Thiazole-Based Heterocycles as Potential Anticancer and Antimicrobial Agents

A novel series of thiazole-based heterocycles was synthesized using 1,3-dipolar cycloaddition reactions in the presence of chitosan-grafted-poly(vinylpyridine) as an eco-friendly biopolymeric basic catalyst. The molecular structure of the synthesized compounds was illustrated by spectroscopic and elemental analysis. Various in vitro biological assays were performed to explore the potential antitumor, antimicrobial and hepatoprotective activities of the newly synthesized compounds. The cytotoxic activities were assessed against human hepatocellular carcinoma (HepG-2), colorectal carcinoma (HCT-116) and breast cancer (MCF-7) cell lines and results revealed that all compounds displayed antitumor activities with the chlorine-containing derivatives, 11c and 6g, being the most potent. The majority of the tested thiazole derivatives exhibited satisfactory antibacterial activity towards the used gram positive and gram-negative bacterial species. Moreover, many derivatives showed weak hepatoprotective activity against CCl₄-induced hepatotoxicity.

Synthesis Under Microwave Irradiation and Molecular Docking of Some Novel Bioactive Thiadiazoles

BACKGROUND

A novel series of fused imidazole was prepared from the reaction of 2- bromoacetyl-3-phenyl-1,3,4-thiadiazole with various heterocyclic amines under microwave irradiation. The structures of all the novel products were elucidated based on the elemental analysis and spectral data.

RESULTS

In addition, the biological activity of the newly synthesized compounds was evaluated and the results obtained indicate their potency as anti-inflammatory, analgesic and anti- ulcer agents.

CONCLUSION

The binding mechanism of the most active compounds was studied using MOE to analyze the molecular interactions.

Eco-Friendly Synthesis, Characterization and Biological Evaluation of Some Novel Pyrazolines Containing Thiazole Moiety as Potential Anticancer and Antimicrobial Agents

The one-pot synthesis of a series of pyrazoline derivatives containing the bioactive thiazole ring has been performed through a 1,3-dipolar cycloaddition reaction of N-thiocarbamoylpyrazoline and different hydrazonoyl halides or α-haloketones in the presence of DABCO (1,4-diazabicyclo[2.2.2] octane) as an eco-friendly catalyst using the solvent-drop grinding method. The structure of the synthesized compounds was elucidated using elemental and spectroscopic analyses (IR, NMR, and Mass). The activity of these compounds against human hepatocellular carcinoma cell line (HepG2) was tested and the results showed that the pyrazoline 11f, which has a fluorine substituent, is the most active. The antimicrobial activities of the newly synthesized compounds were determined against two fungi and four bacterial strains, and the results indicated that some of the newly synthesized pyrazolines are more potent than the standard drugs against test organisms.

Structural Elucidation and Antimicrobial Evaluation of Novel [1,2,4]Triazolo[4,3‐a]pyrimidines and Pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinones

1,3‐Di(thiophen‐2‐yl)prop‐2‐en‐1‐one (1) was utilized in the synthesis of 4,6‐di(thiophen‐2‐yl)‐3,4‐dihydropyrimidine‐2(1H)‐thione (2) and 5,7‐di(thiophen‐2‐yl)‐2‐thioxo‐2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐one (4). The latter thiones were used in the synthesis of two new series of [1,2,4]triazolo[4,3‐a]pyrimidines 10a–i and pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinones 5a–i via reaction with the appropriate hydrazonoyl halides using triethylamine as a basic catalyst in dioxane. The mechanism of formation of the synthesized compounds was discussed, and the assigned structure was established via microanalysis, spectral data (infrared, 1H NMR, and Mass), and density functional calculations. Moreover, the newly synthesized products were evaluated for their antimicrobial activities, and the results show that some derivatives have been well with mild activities. Finally, quantum chemistry calculations confirmed the mechanism and structure of the products.

A facile access and evaluation of some novel thiazole and 1,3,4-thiadiazole derivatives incorporating thiazole moiety as potent anticancer agents

BACKGROUND

Many heterocyclic compounds containing thiazole or 1,3,4-thiadiazole ring in their skeletons have been reported to possess various pharmacological activities especially anticancer activities.

RESULTS

4-Methyl-2-phenylthiazole-5-carbohydrazide (2) was used as a synthon to prepare 2-(4-methyl-2-phenylthiazole-5-carbonyl)-N-phenylhydrazinecarbothioamide (3) and 2-(2-(4-methyl-2-phenylthiazole-5-carbonyl)hydrazono)-N'-phenylpropane hydrazonoyl chlorides 5a-c. In addition, thioamide 3 was used as starting material for preparation of a new series of thiadiazole derivatives via its reaction with hydrazonoyl chlorides 5a-c in dioxane using triethylamines as catalyst. In addition, a series of thiazole derivatives was synthesized by reaction of thioamide 3 with a number of α-halo compounds, namely, 3-chloropentane-2,4-dione (8) or 2-chloro-3-oxo-N-phenyl butanamide (10) phenacyl bromide 12 ethyl chloroacetate (14) in EtOH in the presence of triethylamine. The structures assigned for all the new products were elucidated based on both elemental analyses and spectral data and the mechanisms of their formation was also discussed. Moreover, the new products was evaluated in vitro by MTT assays for their anticancer activity against cell lines of Hepatocellular carcinoma cell line (HepG-2). The best result observed for compounds 7b (IC50 = 1.61 ± 1.92 (μg/mL)) and 11 (IC50 = 1.98 ± 1.22 (μg/mL)). The structure-activity relationships have been suggested based on their anticancer results.

CONCLUSIONS

A novel series of new pharmacophores containing thiazole moiety have been synthesized using a facile and convenient methods and evaluated as potent anticancer agents.

Synthesis, Characterization, and Molecular Docking of Novel bis‐thiazolyl Thienothiophene Derivatives as Promising Cytotoxic Antitumor Drug

A novel, facile reaction for the synthesis of series of bis‐thiazole derivatives has been developed from the reaction of the appropriate thiosemicarbazone derivatives and bis‐2‐bromoacetylthieno[2,3‐b]thiophene derivatives in ethanol under reflux. The structures of the newly synthesized products were established on the basis of spectral data (mass, IR, and 1H and 13C NMR) and elemental analyses. Fifteen compounds of the synthesized compounds were evaluated for their anticancer activity against human liver hepatocellular carcinoma cell line (HepG2). All compounds showed anticancer activity but differs in potency comparable with the reference drug Cisplatin. Moreover, molecular docking study using MOE software predicted the best binding mode between the most active compound 5o into the active site of human heat‐shock protein 90. The computational studies are confirming the results in biological activity.

Ethyl 7-Methyl-1-(4-nitrophenyl)-5-phenyl-3-(thiophen-2-yl)-1,5-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine-6-carboxylate

A novel compound, ethyl 7-methyl-1-(4-nitrophenyl)-5-phenyl-3-(thiophen-2-yl)-1,5-dihydro[1,2,4]triazolo[4,3-a]pyrimidine-6-carboxylate (7) was synthesized by reaction of N-(4-nitrophenyl)thiophene-2-carbohydrazonoyl chloride (1) with ethyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (2). The mechanism of the studied reaction is discussed and the assigned structure was confirmed by elemental analysis and spectral data. Moreover, the in vitro antitumor activities against human lung (A-549) and human hepatocellular carcinoma (HepG-2) cell lines were determined by the MTT method, and the results indicated a high potency compared with the employed standard antitumor drug (Cisplatin).

Microwave-assisted one pot three-component synthesis of some novel pyrazole scaffolds as potent anticancer agents

BACKGROUND

Pyrazoles, thiazoles and 1,3,4-thiadiazoles have been reported to possess various pharmacological activities.

RESULTS

An efficient and a novel approach for the synthesis of some novel pyrazole based-azoles are described via multi-component reaction under controlled microwave heating conditions. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, 1H NMR and mass spectral data. All the synthesized compounds were tested for in vitro activities against two antitumor cell lines, human lung cancer and human hepatocellular carcinoma compared with the employed standard antitumor drug (cisplatin).

CONCLUSIONS

All the newly synthesized compounds were evaluated for their anticancer activity against human lung cancer and human hepatocellular carcinoma cell lines using MTT assay. The results obtained exploring the high potency of six of the tested compounds compared with cisplatin. Graphical abstract Microwave-assisted one pot three-component synthesis of some novel pyrazole scaffolds as potent anticancer agents.

A facile synthesis and anticancer activity of some novel thiazoles carrying 1,3,4-thiadiazole moiety

BACKGROUND

Thiazoles and 1,3,4-thiadiazoles have been reported to possess various pharmacological activities.

RESULTS

A novel series of thiazoles carrying 1,3,4-thiadiazole core were designed and prepared via the reaction of the 2-(4-methyl-2-phenylthiazole-5-carbonyl)-N-phenylhydrazinecarbo-thioamide with the appropriate hydrazonoyl chlorides. The structures of the newly synthesized compounds were confirmed based on elemental and spectral analysis as well as their alternative syntheses. The cytotoxic potency of the newly synthesized thiadiazoles was evaluated by their growth inhibitory potency in liver HepG2 cancer cell line. Also, the structure activity relationship was studied.

CONCLUSIONS

All the newly synthesized compounds were evaluated for their anticancer activity against liver carcinoma cell line (HepG2) using MTT assay. The results revealed that the compounds 12d, 12c, 6g, 18b, 6c, and 6f (IC50 = 0.82, 0.91, 1.06, 1.25, 1.29 and 1.88 µM, respectively) had good antitumor activity against liver carcinoma cell line (HepG2) when compared with the standard drug Doxorubicin (IC50 = 0.72 µM). Graphical abstract A facile synthesis and anticancer activity of some novel thiazoles carrying 1,3,4-thiadiazole moiety.

An Approach to Polysubstituted Triazipines, Thiadiazoles and Thiazoles Based on Benzopyran Moiety Through The Utility of Versatile Hydrazonoyl Halides as In Vitro Monoamine Oxidase Inhibitors

The chromene compound 1 is used as a key intermediate for synthesis of new heterocyclic compounds, and it reacted with hydrazonoyl chlorides in presence of TEA to give the amidrazone derivatives 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, which were cyclized to the corresponding triazepines 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h on boiling with sodium ethoxide. Conversion of compound 1 to the methylthiocarbamate derivative 6 was performed through its reaction with carbon disulfide and KOH followed by treatment with methyl iodide. Compound 6 reacted with hydrazonoyl chlorides in presence of TEA to give thiadiazoles 8a, 8b, 8c, 8d, 8e, 8f, 8g. In addition, chromene 1 combined with aminodithiocarbamic acid in DMF under reflux to furnish the thiosemicarbazide derivative 9, which in turn interacted with several hydrazonoyl chlorides to give the thiazole derivatives 11a, 11b, 11c, 11d, 11e. The structures of the prepared compounds were confirmed from their spectroscopic data and elemental analysis. The synthesized compounds were tested against both monoamine oxidase (MAO)‐A and MAO‐B and corrected to analyses showed good inhibitory activities especially against MAO‐A.

Synthesis and SAR Study of the Novel Thiadiazole-Imidazole Derivatives as a New Anticancer Agents

In the present study, a novel series of 2-(2-(3-aryl-5-substituted-1,3,4-thiadiazol-2(3H)-ylidene)hydrazinyl)-4,4-diphenyl-1H-imidazol-5(4H)-one derivatives were designed and prepared via the reaction of the most versatile, hitherto unreported 2-(5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazol-2-yl)-N-phenylhydrazinecarbothioamide with the appropriate hydrazonoyl halides. In addition, some thiazole derivatives were prepared. The structures of the newly synthesized compounds were established based on spectroscopic evidences and their alternative syntheses. Some of the newly synthesized compounds have been evaluated for their anticancer activity against a liver carcinoma cell line HEPG2-1. Moreover, their structure-activity relationship (SAR) was explored for further development in this area. The results indicated that many of the tested compounds showed moderate to high anticancer activity with respective to doxorubicin as a reference drug. Consequently, the new synthesized series of thiadiazole-imidazole derivatives are considered as powerful anticancer agents.

Utility of Pyrazolylchalcone Synthon to Synthesize Azolopyrimidines under Grindstone Technology

A series of pyrazolyl-triazolo[1,5-a]pyrimidines, pyrazolyl-tetrazolo[1,5-a]pyrimidines, pyrazolyl-benzo[4,5]imidazo[1,2-a]pyrimidines and bis-azolopyrimidines were prepared by reaction of pyrazolyl-chalcones or its bis-pyrazolyl-chalcones with the appropriate heterocyclic amines as aminotriazole, aminotetrazole, 2-aminobenzimidazole and 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-amine by grinding method. The newly synthesized compounds have been characterized on the basis of elemental analysis and spectral data (IR, ¹H- and ¹³C-NMR, Mass). Moreover, the newly synthesized products were screened for their in vitro antibacterial activities and the results showed that compounds 5f and 11d exhibited excellent activities compared with penicillin G and streptomycin as reference drugs.

Synthesis and Characterization of Some New Bis-Pyrazolyl-Thiazoles Incorporating the Thiophene Moiety as Potent Anti-Tumor Agents

A new series of 1,4-bis(1-(5-(aryldiazenyl)thiazol-2-yl)-5-(thiophen-2-yl)-4,5-dihydro-1H-pyrazol-3-yl)benzenes 3a-i were synthesized via reaction of 5,5'-(1,4-phenylene)bis(3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-carbothioamide) (1) with hydrazonoyl halides 2a-i. In addition, reaction of 1 with ethyl chloroacetate afforded bis-thiazolone derivative 8 as the end product. Reaction of compound 8 with methyl glyoxalate gave bis-thiazolone derivative 10. The structures of the newly synthesized compounds were established on the basis of spectroscopic evidences and their alternative syntheses. All the synthesized compounds were evaluated for their anti-tumor activities against hepatocellular carcinoma (HepG2) cell lines, and the results revealed promising activities of compounds 3g, 5e, 3e, 10, 5f, 3i, and 3f with IC50 equal 1.37 ± 0.15, 1.41 ± 0.17, 1.62 ± 0.20, 1.86 ± 0.20, 1.93 ± 0.08, 2.03 ± 0.25, and 2.09 ± 0.19 μM, respectively.

Heterocyclisation of 2,5-diacetyl-3,4-disubstituted-thieno[2,3-b]Thiophene Bis-Thiosemicarbazones Leading to Bis-Thiazoles and Bis-1,3,4-thiadiazoles as Anti-breast Cancer Agents

In this paper, the synthesis of bis-thiazoles and bis-1,3,4-thiadiazoles linked to a thienothiophene nucleus is described. The synthesis was achieved through interaction between 2,5-diacetylthieno[2,3-b]thiophene bis-thiosemicarbazones with a variety of hydrazonyl halides in a basic medium. All the synthesised compounds were characterised by IR, 1H NMR, 13C NMR and mass spectroscopic analyses. The newly synthesised compounds represent a variety of novel polyheteroatomic moieties containing nitrogen and sulfur. Most of the synthesised compounds were evaluated for their antitumour activity against the breast cancer MCF-7 cell line. The results revealed that four compounds are equipotent to tamoxifen (IC50 = 8.04 μg mL−1) with IC50 = 8.23, 8.26, 8.68 and 9.12 μg mL−1 respectively.

Synthesis, Characterization and Molecular Docking of Novel Bioactive Thiazolyl-Thiazole Derivatives as Promising Cytotoxic Antitumor Drug

Reactions of ethylidenethiocarbohydrazide with hydrazonoyl halides gave 1,3-thiazole or 1,3,4-thiadiazole derivatives according to the type of hydrazonoyl halides. Treatment of ethylidenethiosemicarbazide with hydrazonoyl halides and dimethylacetylene dicarboxylate (DMAD) afforded the corresponding arylazothiazoles and 1,3-thiazolidin-4-one derivatives, respectively. The structures of the synthesized products were confirmed by IR, ¹H-NMR, ¹³C-NMR and mass spectral techniques. The cytotoxic activity of the selected products against the Hepatic carcinoma cell line (Hepg-2) was determined by MTT assay indicating a concentration dependent cellular growth inhibitory effect, especially for compounds 14c and 14e. The dose response curves indicated the IC₅₀ (the concentration of test compounds required to kill 50% of cell population) were 0.54 μM and 0.50 μM, respectively. Confocal laser scanning imaging of the treated cells stained by Rhodamin 123 and Acridine orange dyes confirmed that the selected compounds inhibit the mitochondrial lactate dehydrogenase enzymes. The binding mode of the active compounds was interpreted by a molecular docking study. The obtained results revealed promising cytotoxic activity.

Synthesis and Characterisation of Some Novel Fused Thiazolo[3,2-A] Pyrimidinones and Pyrimido[2,1-B][1,3]Thiazinones

Reactions of 7,9-bis(4-methoxyphenyl)-2-thioxo-2,3-dihydropyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-4(1H)-one with α-haloketones, chloroacetonitrile and DMAD, afforded the corresponding fused thiazolo[3,2-a]pyrimidinone derivatives. The reaction of the thione with chloroacetic acid and an appropriate aromatic aldehyde yielded the respective 2-arylidene-2H-pyrido[3′,2′:4,5]thieno[3,2-d]thiazolo[3,2-a] pyrimidine-3,5-diones. Also, the treatment of thione with arylidenemalononitriles gave the fused pyrimido[2,1-b][1,3]thiazine derivatives, respectively. The structures of the synthesised products were confirmed by IR, 1H NMR and mass spectral techniques. The cytotoxic activity of the new products against breast carcinoma (MCF-7) and hepatocellular carcinoma (HepG2) cell lines were determined and the results revealed promising activity.

Identification of novel aminothiazole and aminothiadiazole conjugated cyanopyridines as selective CHK1 inhibitors

Inhibitors of checkpoint kinase 1 (CHK1) are of current interest as potential anti-tumor agents. Novel series of cyanopyridyl-aminothiadiazoles (synthesized from reaction of 1-(3-cyano-4,6-diphenylpyridin-2-yl)-3-phenylthiourea (14) with hydrazonoyl halides) and cyanopyridyl-aminothiazolyl-thiadiazoles (synthesized from treatment of 14 with ethyl chloroacetate followed by reaction of the obtained cyanopyridyl-aminothiazole with hydrazonoyl halides) were synthesized and evaluated for their CHK1 inhibitory potential using a cell-based assay cascade. The tested compounds exhibited a potent and selective CHK1 inhibitory activity at nanomolar levels that reflected their ability to abrogate cell cycle arrest and potentiate the cytotoxic effect of the genotoxic drug gemcitabine in colon cancer cells. Molecular modeling simulation revealed that, the most active compound 28a docked well into the enzyme active site and their complex is stabilized by a key H-bonding with the backbone amide of Cys-87 as well as multiple favorable hydrophobic interactions with different hydrophobic binding regions of the enzyme.

Novel pyrrole derivatives as selective CHK1 inhibitors: design, regioselective synthesis and molecular modeling

3D binding interactions of 7a (magenta-colored carbons) and the co-crystallized ligand (cyan-colored carbons) with the active site amino acids of CHK1.