Evaluation of the Binding Relationship of the RdRp Enzyme to Novel Thiazole/Acid Hydrazone Hybrids Obtainable through Green Synthetic Procedure

The viral RNA-dependent RNA polymerase (RdRp) complex is used by SARS-CoV-2 for genome replication and transcription, making RdRp an interesting target for developing the antiviral treatment. Hence the current work is concerned with the green synthesis, characterization and docking study with the RdRp enzyme of the series of novel and diverse hydrazones and pyrazoles. 4-Methyl-2-(2-(1-phenylethylidene)hydrazineyl)thiazole-5-carbohydrazide was prepared and then condensed with different carbonyl compounds (aldehydes and ketones either carbocyclic aromatic or heterocyclic) afforded the corresponding hydrazide-hydrazones. The combination of the acid hydrazide with bifunctional reagents such as acetylacetone, β-ketoesters (ethyl acetoacetate and ethyl benzoylacetate) resulted in the formation of pyrazole derivatives. The synthesized compounds were all obtained through grinding method using drops of AcOH. Various analytical and spectral analyses were used to determine the structures of the prepared compounds. Molecular Operating Environment (MOE^®) version 2014.09 was used to estimate interactions between the prepared thiazole/hydrazone hybrids and RdRp obtained from the protein data bank (PDB: 7bv2) using enzyme-ligand docking for all synthesized derivatives and Remdesivir as a reference. Docking results with the RdRp enzyme revealed that the majority of the investigated drugs bind well to the enzyme via various types of interactions in comparison with the reference drug.

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.

Clean Grinding Technique: A Facile Synthesis and In Silico Antiviral Activity of Hydrazones, Pyrazoles, and Pyrazines Bearing Thiazole Moiety against SARS-CoV-2 Main Protease (Mpro)

A novel series of some hydrazones bearing thiazole moiety were generated via solvent-drop grinding of thiazole carbohydrazide 2 with various carbonyl compounds. Also, dehydrative-cyclocondensation of 2 with active methylene compounds or anhydrides gave the respective pyarzole or pyrazine derivatives. The structures of the newly synthesized compounds were established based on spectroscopic evidences and their alternative syntheses. Additionally, the anti-viral activity of all the products was tested against SARS-CoV-2 main protease (M^pro) using molecular docking combined with molecular dynamics simulation (MDS). The average binding affinities of the compounds 3a, 3b, and 3c (−8.1 ± 0.33 kcal/mol, −8.0 ± 0.35 kcal/mol, and −8.2 ± 0.21 kcal/mol, respectively) are better than that of the positive control Nelfinavir (−6.9 ± 0.51 kcal/mol). This shows the possibility of these three compounds to effectively bind to SARS-CoV-2 Mpro and hence, contradict the virus lifecycle.

Synthesis of novel naphthalene-heterocycle hybrids with potent antitumor, anti-inflammatory and antituberculosis activities

Multitarget-directed drugs (hybrid drugs) constitute an efficient avenue for the treatment of multifactorial diseases. In this work, novel naphthalene hybrids with different heterocyclic scaffolds such as nicotinonitrile, pyran, pyranopyrazole, pyrazole, pyrazolopyridine, and azepine were efficiently synthesized via tandem reactions of 3-formyl-4H-benzo[h]chromen-4-one 1 with different nucleophilic reagents. Analysis of these hybrids using PASS online software indicated different predicted biological activities such as anticancer, antimicrobial, antiviral, antiprotozoal, anti-inflammatory, etc. By focusing on antitumor, anti-inflammatory, and antituberculosis activities, many compounds revealed remarkable activities. While 3c, 3e, and 3h were more potent than doxorubicin in the case of HepG-2 cell lines, 3a–e, 3i, 6, 8, 10, 11, and 12b were more potent in the case of MCF-7. Moreover, compounds 3c, 3h, 8, 10, 3d, and 12b manifested superior activity and COX-2 selectivity to the reference anti-inflammatory Celecoxib. Regarding antituberculosis activity, 3c, 3d, and 3i were found to be the most promising with MIC less than 1 μg mL⁻¹. The molecular docking studies showed strong polar and hydrophobic interactions with the novel naphthalene-heterocycle hybrids that were compatible with experimental evaluations to a great extent.

Novel naphthalene-heterocycle hybrids were synthesized via tandem reactions of 3-formylchromone with different nucleophilic reagents. Various hybrids revealed potent antitumor and anti-inflammatory as well as promising antituberculosis activities.

Design, Synthesis, Molecular Docking Study and Anti-Hepatocellular Carcinoma Evaluation of New Bis-Triazolothiadiazines

OBJECTIVE

The reaction of bis(4-amino-4H-1,2,4-triazole-3-thiol) with hydrazonoyl halides and α-halo-ketones gave a new series of bis-1,2,4-triazolo[3,4-b]thiadiazine derivatives.

METHODS

The structure of the new products was established on the basis of their elemental and spectral data (mass, 1H NMR, 13C NMR and IR) and an alternate method.

RESULTS

Several of the synthesized products were subjected to in vitro anticancer screening against human hepatocellular carcinoma (HepG-2) and the results showed that compounds 16, 14 and 12 have promising activities (IC50 value of 24.8±9.1, 28.3±0.5, and 31±2.9μM, respectively) compared with Harmine reference drug (IC50 value of 22.4±1.11 μM).

CONCLUSION

Moreover, molecular docking studies were performed to analyze the binding modes of the discovered hits into the active site of DYRK1A using iGEMDOCK.

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.

Synthesis of some new pyrazolo[1,5-a]pyrimidine, pyrazolo[5,1-c]triazine, 1,3,4-thiadiazole and pyridine derivatives containing 1,2,3-triazole moiety

Background

Pyrazolo[1,5-a]pyrimidines are purine analogues. They have beneficial properties as antimetabolites in purine biochemical reactions. This division compounds have attracted wide pharmaceutical interest because of their antitrypanosomal activity.

Results

The present work depicts an effective synthesis convention of pyrazolo[1,5-a]pyrimidines, pyrazolo[5,1-c]triazines, thieno[2,3-b]pyridines and polysubstituted pyridines containing 1,2,3,-triazole moiety from the reaction of sodium 3-(5-methyl-1-(p-toly)-1H-1,2,3-triazol-4-yl)-3-oxoprop-1-en-1-olate with the fitting heterocyclic amines and its diazonium salt, and active methylene compounds, individually. Likewise, thiazoles and, 1,3,4-thiadiazoles were obtained from 2-bromo-1-(5-methyl-1-(p-tolyl)-1H-1,2,3-triazol-4-yl)ethanone and some reagent such as hydrazonoyl chlorides and halo ketones. The newly synthesized compounds were established by elemental analysis, spectral data, and alternative synthetic route whenever possible.

Conclusions

New series of pyrazolo[1,5-a]pyrimidines, pyrazolo[5,1-c]triazines, thieno[2,3-b]pyridines and polysubstituted pyridines containing the 1,2,3,-triazole moiety were synthesized via reactions of sodium 3-(5-methyl-1-(p-toly)-1H-1,2,3-triazol-4-yl)-3-oxoprop-1-en-1-olate with the appropriate heterocyclic amines and its diazonium salt. In addition, 1,3,4-thiadiazoles and, 1,3-thiazoles were acquired in a decent yield via the reaction of substituted thiourea with the appropriate hydrazonoyl chlorides and halogenated ketenes.Graphical abstract

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-017-0255-7) contains supplementary material, which is available to authorized users.

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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 of New 3-Heteroarylindoles as Potential Anticancer Agents

2-(3-(1H-Indol-3-yl)-5-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)-4-substituted-5-(substituted diazenyl)thiazoles and 2-(1H-indol-3-yl)-9-substituted-4,7-disubstituted pyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrimidin-5(7H)-ones were synthesized via reaction of hydrazonoyl halides with each of 3-(1H-indol-2-yl)-5-(p-tolyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide and 7-(1H-indol-3-yl)-2- thioxo-5-substituted-2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-ones, respectively. Also, hydrazonoyl halides were reacted with N’-(1-(1H-indol-3-yl)ethylidene)-2-cyanoacetohydrazide to afford 1,3,4-thiadiazole derivatives. Structures of the new synthesis were elucidated on the basis of elemental analysis, spectral data, and alternative synthetic routes whenever possible. Fifteen of the new compounds have been evaluated for their antitumor activity against the MCF-7 human breast carcinoma cell line. The results indicated that many of the tested compounds showed moderate to high anticancer activity when compared with doxorubicin as a reference drug.

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.

Synthesis of New Functionalised Derivatives of [1,2,4]triazolo[4,3-a]Pyrimidine and Pyrimido[2,1-b][1,3,5]Thiadiazine as Aromatase Inhibitors

New functionalised 3,4-dihydropyrimido[2,1-b][1,3,5]thiadiazine-6,8-(2H,7H)-dione and [1,2,4]triazolo[4,3-a]pyrimidine-5,7-(1H,6H)-dione derivatives were synthesised through the reaction of thiobarbituric acid with aromatic amines and formaldehyde and from thiobarbituric acid and hydrazonoyl halides, respectively. The structures of the target compounds were confirmed by 1H NMR, IR and MS spectra. Moreover, the newly synthesised products were tested for their aromatase inhibition activities and the results obtained were promising compared with the drug letrozole, a non-steroidal aromatase inhibitor.

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.

Synthesis and cytotoxicity evaluation of some novel thiazoles, thiadiazoles, and pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5(1H)-ones incorporating triazole moiety

Reactions of hydrazonoyl halides and each of methyl 2-(1-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)ethylidene)hydrazine-1-carbodithioate and 2-(1-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)ethylidene)hydrazine-1-carbothioamide afforded 2-(1-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)ethylidene)hydrazono)-3-phenyl-5-substituted-2,3-dihydro-1,3,4-thiadiazoles and 5-(4-substituted)diazenyl)-2-(2-(1-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)ethylidene)hydrazinyl)-4-arylthiazoles, respectively. Analogously, the reactions of hydrazonoyl halides with 7-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-5-phenyl-2-thioxo-2,3-dihydropyrido[2,3-d]pyrimidin-4(1H)-one gave 3-(4-substituted)-8-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-6-phenyl-1-arylpyrido[2,3-d]-[1,2,4]-triazolo-[4,3-a]pyrimidin- 5(1H)-ones in a good yield. The structures of the newly synthesized were elucidated via elemental analysis, spectral data and alternative synthesis routes whenever possible. Twelve of the newly synthesized compounds have been evaluated for their antitumor activity against human breast carcinoma (MCF-7) and human hepatocellular carcinoma (HepG2) cell lines. Their structure activity relationships (SAR) were also studied. The 1,3,4-thiadiazole derivative 9b (IC50 = 2.94 µM) has promising antitumor activity against the human hepatocellular carcinoma cell line and the thiazole derivative 12a has promising inhibitory activity against both the human hepatocellular carcinoma cell line and the breast carcinoma cell line (IC50 = 1.19, and 3.4 µM, respectively).

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.

Synthesis of Novel Indolizine, Pyrrolo[1,2-A] Quinoline, and 4,5-Dihydrothiophene Derivatives Via Nitrogen Ylides and their Antimicrobial Evaluation

Treatment of 2-(2-bromoacetyl)-3 H-benzo[ f]chromen-3-one with pyridine, quinoline, and 2-methylquinoline afforded the corresponding pyridinium, quinolinium and 2-methylquinolinium bromides. The latter salts underwent [3 + 2] 1,3-dipolar cycloaddition with some electron deficient acetylene and ethylene derivatives to give the corresponding indolizine and pyrrolo[1,2- a]quinoline derivatives. Moreover, 2-(2-bromoacetyl)-3 H-benzo[ f]chromen-3-one reacted with arylidene cyanothioacetamides to afford the corresponding 2-amino-4,5-dihydrothiophene-3-carbonitriles. The synthesised compounds were characterised based on their elemental analysis and spectral data. Antimicrobial activity of some of the synthesised compounds was evaluated.