Synthesis and antimicrobial study of fluoroquinolone-based 4-thiazolidinones

The title compounds 2-substituted phenyl-3-{1-cyclopropyl-6-fluoro-7-[4-(4-methoxyphenylpiperazin-1-yl]-4-oxo-1,4-dihydroquinoline} carboxamido-1,3-thiazolidin-4-ones 6a–j have been synthesized from lead molecule 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 1; this reacted with thionyl chloride to give acid chloride 2 and with hydrazine hydrate to afford hydrazide 3. The hydrazide 3 on condensation with substituted aromatic aldehydes a–j gave Schiff base; these on reaction with N-(4-methoxyphenyl) piperazine and thioglycolic acid furnished title compounds 6a–j. All of the synthesized compounds have been established by elemental analysis. IR and NMR spectral data and have been screened for antifungal and antibacterial activities.     

Synthesis and docking studies of N-(5-(alkylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamide analogues as potential alkaline phosphatase inhibitors

A series of N-(5-(alkylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamides 6a–i were synthesized as alkaline phosphatase inhibitors. The intermediate 5-substituted 1,3,4-oxadiazole-2-thione 4 was synthesized starting with hippuric acid. Hippuric acid in the first step was converted into corresponding methyl ester 2 which upon reaction with hydrazine hydrate furnished the formation of hydrazide 3 . The hippuric acid hydrazide was then cyclized into 5-substituted 1,3,4-oxadiazole-2-thione 4 . The intermediate 4 was then reacted with alkyl or aryl halides 5a–5i to afford the title compounds N-(5-(methylthio)-1,3,4-oxadiazol-2-yl)methyl)benzamides 6a–i . The bioassay results showed that compounds 6a–i exhibited good to excellent alkaline phosphatase inhibitory activity. The most potent activity was exhibited by the compound 6i having IC₅₀ value 0.420 μM, whereas IC₅₀ value of standard (KH₂PO₄) was 2.80 μM. Molecular docking studies was performed against alkaline phosphatase enzyme (PDBID 1EW2) to check binding affinity of the synthesized compounds 6a–i against target protein. The docking results showed that three compounds 6c , 6e , and 6i have maximum binding interactions with binding energy values of −8 kcal/mol. The compound 6i displayed the interactions of oxadiazole ring nitrogen with amino acid His265 having a binding distance 2.13 Ǻ. It was concluded from our results that synthesized compounds, especially compound 6i may serve as lead structure to design more potent inhibitors of human alkaline phosphatase.     

Synthesis and anti-HIV activity of 4-[(1,2-dihydro-2-oxo-3H-indol-3-ylidene) amino]-N(4,6-dimethyl-2-pyrimidinyl)-benzene sulfonamide and its derivatives

4-[(1,2-Dihydro-2-oxo-3H-indol-3-ylidene) amino]-N(4,6-dimethyl-2-pyrimidinyl)-benzene sulphonamide and its derivatives were synthesized by reaction of isatin and its derivatives with sulphadimidine. Their chemical structures have been confirmed by IR, ¹H NMR data and elemental analysis. Investigation of anti-HIV activity of compounds were tested against replication of HIV-1 (IIIB) and HIV-2 (ROD) strains in acutely infected MT-4 cells and the activity compared with standard azidothymidine. Among the compounds tested, 4-[(1,2-dihydro-2 oxo-3H-indol-3-ylidene)amino]-N(4,6-dimethyl-2-pyrimidinyl)-benzene sulphonamide and its N-acetyl derivative were the most active compounds.     

5-Nitro-heteroarylidene analogs of 2-thiazolylimino-4-thiazolidinones as a novel series of antibacterial agents

In the pursuit of novel antibacterial agents with the 2-thiazolylimino-4-thiazolidinone as a core structure, a series of 5-nitro-heteroarylidene and 5-(2-oxoindolin-3-ylidene) analogs of 2-thiazolylimino-5-arylidene-4-thiazolidinone were synthesized and their antibacterial activities were evaluated against some strains of Gram-positive and Gram-negative bacteria, as well as Helicobacter pylori strains. Biological data indicated that 5-nitrofuran analog 5a and 5-nitroimidazole analog 7a containing no substitutions on the thiazole ring were the most potent compounds.     

Synthesis and anti-HIV evaluation of the novel 2-(m-chlorobenzyl)-4-substituted-7-methyl-1, 1, 3-trioxo-pyrazolo[4, 5-e] [1, 2, 4]thiadiazines

A novel series of 2-(m-Chlorobenzyl)-4-substituted-1, 1, 3-trioxo-2H,4H-pyrazolo[4, 5-e][1, 2, 4] thiadiazines (7a-k) were synthesized, and evaluated for their anti-HIV replication in MT-4 cell cultures. Compound (7a) showed activity against HIV-1-induced cytopathicity, with an EC₅₀ value of 45.6 μM, but none of the compounds exhibited inhibitory activity against HIV-2.     

Synthesis,Characterization, and Cytotoxicity of Some New 5-Aminopyrazole and Pyrazolo[1,5-a]pyrimidine Derivatives

5-Amino-N-aryl-3-[(4-methoxyphenyl)amino]-1H-pyrazole-4-carboxamides 4a–c were synthesized by the reaction of N-(aryl)-2-cyano-3-[(4-methoxyphenyl)amino]-3-(methylthio)acrylamides 3a–c with hydrazine hydrate in ethanol. The reaction of 5-amino-N-aryl-1H-pyrazoles 4a–c with acetylacetone 5 or 2-(4-methoxybenzylidene)malononitrile 8 yielded the pyrazolo[1,5-a]pyrimidine derivatives 7a–c and 10a–c, respectively. The structures of the synthesized compounds were established based on elemental analysis and spectral data (IR, MS, ¹H-NMR, and ¹³C-NMR). Representative examples of the new synthesized products were screened for their in vitro cytotoxic activity against Ehrlich Ascites Carcinoma (EAC) cells.     

Synthesis of novel 2-substituted quinoline derivatives: antimicrobial, inotropic, and chronotropic activities

Three novel series of quinoline derivatives have been prepared by cyclization of the intermediate 3-(1,3-dioxolan-2-yl)-2-substituted thiocarbamoyl-hydrazinoquinolines with different alpha-halocarbonyl compounds. These series are: 3-(1,3-dioxolan-2-yl)-2-(3-substituted-4-phenylthiazolin-2-y lidene) hydrazinoquinolines; 3-(1,3-dioxolan-2-yl)-2-(3-substituted-5-ethoxycarbonyl- 4-methylthiazoline-2-ylidene)hydrazinoquinolines and 3-(1,3-dioxolan-2-yl)-2- (3-substituted-4-thiazolidinon-2-yl)hydrazinoquinolines. The active methylene group of the latter series was used for the preparation of their arylidene derivatives. The antimicrobial as well as inotropic and chronotropic activities of the prepared compounds were studied.     

Synthesis of thiazolo[4,5-d]pyrimidine derivatives as potential antimicrobial agents

In this study, we report the synthesis and antimicrobial evaluation of several new thiazolo[4,5-d]pyrimidine derivatives, namely 7-substituted amino-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 4a-e, 8, 13, 15, ethyl 2-cyano-2-(7-substituted-5-methyl-3-phenylthiazolo [4,5-d]-pyrimidin-2(3H)-ylidene)acetates 5a-b, 2-(7-substituted-5-methyl-3-phenylthiazolo[4,5-d]pyrimidin-2(3H)-ylidene)malononitriles 6a-b, 5-methyl-7-morpholino-3-phenylthiazolo[4,5-d] pyrimidine-2(3H)-one 7, and 7-[4-(1-substituted-5-phenyl-4,5-dihydro-1H-pyrazolin-3-yl)anilino]-5-methyl-3-phenylthiazolo[4,5-d]pyrimidine-2(3H)-thiones 10-12. Some of the tested compounds were more active against C. albicans than E. coil and P. aeruginosa, and all were inactive against S. aureus.     

Synthesis and evaluation of the hypoglycemic and hypolipidemic activity of novel 5-benzylidene-2,4-thiazolidinedione analogs in a type-2 diabetes model

This article reports synthesis and evaluation of two novel thiazolidinedione ring containing molecules namely (Z)-5-(2-(4-((2,4-dioxothiazolidin-5-ylidene)methyl)phenoxy)acetyl)-2-hydroxybenzamide (4) and (Z)-2-(4-((2,4-dioxothiazolidin-5-ylidene)methyl)phenoxy)-N-(5-nitrothiazol-2-yl)acetamide (7). The new chemical entities were tested for hypoglycemic activity and for their total cholesterol (CHL) and triglyceride (TG) lowering effect in high-fat diet (HFD) fed Sprague–Dawley rats. The synthesized molecules showed significant reduction in blood glucose, CHL, and TG levels after 14 days of treatment.     

Synthesis and antimicrobial activity of new pyridine derivatives-I

2-Amino substituted benzothiazoles 2a–l and 2-chloropyridine-3-carboxylic acid 3 were used to prepare 2-[N-(substitutedbenzothiazolyl)amino]pyridine-3-carboxylic acids (4a–l) in 2-ethoxy ethanol. Acid chlorides (5a–l) were condensed with 2-hydroxyethyl piperazine (6) and 2,3-dichloropiperazine (7) to prepare amide derivatives 2-[N-(substituted benzothiazolyl)amino]pyridin-3-yl(4-(2-hydroxyethyl)piperazin-1-yl)methanones (8a–l) and 2-[N-(substituted benzothiazolyl) amino]pyridin-3-yl(2,3-dichloropiperazine-1-yl)methanones (9a–l), respectively. The structures of new compounds have been established on the basis of elemental analysis and spectral (IR, ¹H NMR, and Mass spectra) studies. The in vitro antimicrobial activity was screened for all the synthesized compounds. Variable and modest activity were observed against the investigated strains of bacteria and fungi.     

Synthesis and antiviral activity of new 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids derivatives

The synthesis of new 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (3a-l) derivatives and the new 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (5a–c) derivatives was achieved with an efficient synthetic route. Ethyl 4-chloro-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1) on fusion with appropriate substituted anilines or aminopicolines gave the required new ethyl 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (2a–l) (52–82%) or new ethyl 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (4a–c) (50–60%), respectively. Subsequent hydrolysis of the esters afforded the corresponding carboxylic acids (3a–l) (86–93%) and (5a–c) in high yield (80–93%). Inhibitory effects of 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids. Derivatives on Herpes simplex virus type 1 (HSV-1), Mayaro virus (MAY) and vesicular stomatitis virus (VSV) were investigated. Compounds 2d, 3f, 3a, and 3c exhibited antiviral activity against HSV-1, MAY, and VSV virus with EC₅₀ values of 6.8, 2.2, 4.8, 0.52, 2.5, and 1.0. None of these compounds showed toxicity for Vero cells.     

Synthesis of benzimidazole derivatives as potential antimicrobial agents

Three novel series of benzimidazol derivatives were prepared. Namely; 2-alkyl-1-(4-substituted-4H-1,2,4-triazole-5-thion-3-yl)methylb enzimidazoles; 2-alkyl-1-(5-substituted amino-1,3,4-thiadiazol-2-yl)methylbenzimidazoles; and 2-alkyl-1-[(3,4-disubstituted thiazolin-2-ylidene)hydrazinocarbonyl] methylbenzimidazoles. The antimicrobial testing of the prepared compounds as well as of the key intermediate thiosemicarbazides was performed.     

Novel thiazolinyl, thiazolidinonyl, thiadiazolyl and oxadiazolyl-benzotriazole derivatives with potential antiinflammatory activity and minimum ulcerogenic effect

Four novel series of 1H-benzotriazole derivatives; containing thiazolin, thiazolidin, thiadiazole and oxadiazole moieties; namely 1-[(3,4-disubstituted thiazolin-2-ylidene)hydrazinocarbonyl]methyl-1H-benzotriazoles 3a-1; 1-[3-substituted 5-ethoxycarbonyl-4-methyl thiazolin-2-ylidene)hydrazinocarbonyl]methyl-1H-benzotriazoles 4a-c; 1-[(3-substituted-4-oxothiazolidin-2-ylidene)hydrazinocarbonyl]methyl-1H- benzotriazoles 5a-d; 1-[(5-substituted aminothiadiazol-2-yl)methyl]-1H-benzotriazoles 6a-c have been synthesized by cyclization of the key intermediates 1-[(substituted thiocarbamoylhydrazinocarbonyl)methyl]-1H-benzotriazoles 2a-d. Furthermore 1-[(5-substituted aminooxadiazol-2-yl)methyl]-1H-benzotriazoles 7a, b were obtained by one-pot synthesis starting from 1H-benzotriazol-1-acetic acid hydrazide. The antiinflammatory activity of representative compounds was evaluated in vivo against indomethacin as a standard using the sponge implantation model of inflammation in rats. Both non-immunological parameters such as exudate volume, total leucocyte count (TLC), and differential leucocyte count (DLC), and immunological parameters, for example neutrophil phagocytic function by reduced cytochrome C levels, and the assay of interleukin-1 beta (IL-1 beta) levels in drug-pre-treated rats, were determined. The ulcerogenic activity of compounds showing marked antiinflammatory activity was also studied. Compounds 3e, 5b and 5c showed antiinflammatory activity comparable to indomethacin, and they also demonstrated minimum ulcerogenic activity.     

Synthesis and characterization of flurbiprofen hydrazide derivatives as potential anti-HCV, anticancer and antimicrobial agents

A novel series of new flurbiprofen hydrazide derivatives 2-(2-fluorobiphenyl-4-yl)-N′-[(substituted phenyl/5-nitro-2-furyl)methylene]propanehydrazide (3a–k), 2-(2-fluorobiphenyl-4-yl)-N-(2-substituted-4-oxo-1,3-thiazolidine-3-yl)propanamide (4a–b, 4d–k), 2-[2-(2-fluorobiphenyl-4-yl) propanoyl]-N-substituted hydrazinecarbothioamide (5a–h) and 2-(2-fluorobiphenyl-4-yl)-N′-[(3-methyl-4-oxo-1,3-thiazolidin-2-ylidene]propanehydrazide (6a–b, 6e and 6g) has been synthesized in this study. All synthesized compounds were screened for antimicrobial activity against various bacterial and fungal strains. Additionally, compounds were evaluated for the ability to inhibit Hepatitis C virus NS5B polymerase. The most active 4-thiazolidinone compound was 4k (SGK119) with 67.0 % and thiosemicarbazide compound was 5d (SGK123) with 69.50 % inhibition at 200 μM against hepatitis C virus NS5B RNA polymerase. Anticancer activity of the selected compounds (3i, 3j, 3h, 4d, 4i and 6b) was determined at a single dose towards the full panel of 60 human cancer cell lines by the National Cancer Institute (NCI). 2-(2-Fluoro-4-biphenylyl)-N-[2-[4-(trifluoromethyl)phenyl]-4-oxo-1,3-thiazolidine-3-yl]propanamide 4d, containing thiazolidinone ring, demonstrated the most marked effect with 20.80 % growth percent on leukaemia cancer cell line SR at 10^?5 M. The results demonstrated that none of the compounds tested have anticandidal and antifungal activities, but two of them (4a and 4i) showed antibacterial inhibition against Micrococcus luteus, and Staphylococcus cohnii and Staphylococcus aureus, respectively.     

Synthesis and evaluation of antitumor activity of novel 2-[<Emphasis Type="Italic">N</Emphasis>-Methyl-<Emphasis Type="Italic">N</Emphasis>-(4-methyl-1,3-benzothiazol-2-yl)aminomethyl]-5,8-diacyloxy-1,4-naphthoquinones

A series of nine new compounds bridged by acyl groups at the 5,8-dihydroxyl group of DHNQ were synthesized and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor action in mice bearing S-180 cells in the peritoneal cavity was also assessed. Increasing the size of the acyl group (compounds 7–9) up to propyl increased the antitumor activity (T/C value), whereas the cytotoxicity of these compounds was comparable against L1210 (lymphocytic leukemia) and P388 (lymphoid neoplasm) cancer cells. Further increasing in the chain length (compounds 11–15) decreased the potency. Thus, acyl group chains of three carbon atoms is optimal for antitumor activity. The most potent compound of this series was 2-[N-methyl-N-(4-methyl-1,3-benzothiazol-2-yl)aminomethyl]-5,8-dipropylcarbonyloxy-1,4-naphthoquinone (compound 9) with a T/C (%) value of 354.     

Microwave-assisted synthesis and evaluation of anti-inflammatory activity of new series of N-substituted 2-butyl-5-chloro-3H-imidazole-4-carbaldehyde derivatives

A series of N-substituted 2-butyl-5-chloro-3H-imidazole-4-carbaldehyde derivatives bearing potentially bioactive substituents were synthesized by microwave irradiation method in good yield compared with conventional method. The synthesized compounds were screened for their anti-inflammatory activity and were compared with a standard drug. The compounds demonstrated potent to weak anti-inflammatory activity. Of the compounds studied, compounds 6i and 6d showed potent activity comparable to the standard drug ibuprofen at the same dose in carrageenan-induced paw edema in rat model.     

Synthesis characterization and biological evaluation of some alkoxyphthalimide derivatives of 3-(4-substituted phenyl)-6,6-diphenyl-3,3a-dihydro-2H-imidazo[2,1-b]pyrazolo[3,4-d][1,3]thiazol-7(6H)-one

A series of 2-N-ethoxyphthalimido 3-(4-substitutedphenyl)-6,6-diphenyl-3,3a-dihydro-2H-imidazo[2,1-b]pyrazolo[3,4-d][1,3]thiazol-7(6H)-one(7a–e) and 4-(4-substituted phenyl)-2-(N-ethoxyphthalimido amino)-7,7-diphenylimidazo[2′,1′:2,3][1,3]thiazolo[4,5-d] pyrimidin-8(7H)-one (9a–e) have been designed and synthesized starting from thiohydentoin (1). The structure of all synthesized compounds has been established by IR, ¹H NMR, ¹³C NMR and mass studies. These compounds have been screened for antimicrobial activities in order to evaluate the possibility of the derivatives to be used as potential chemotherapeutic agents.     

Synthesis and Antitumor Activity of Some New 2-Chloroethylnitrosoureas

The synthesis of a series of N-(2-chloroethyl)-N′-(9H-xanthen-9-yl)-N-nitrosoureas and N-(2-chloroethyl)-N′-(9H-thioxanthen-9-yl)-N-nitrosoureas is described. The title compounds were evaluated against NSCLCN6 L16 bronchial epidermoid carcinoma in vitro and some of them were found to be active. N-(2-chloroethyl)-N′-(2-methoxy-9H-xanthen-9-yl)-N-nitrosourea ( 8e ) was active against leukemia P388 tumor system in mice.     

Synthesis, anticonvulsant and neurotoxic activity of some new 2,5-disubstituted-1,3,4-oxadiazoles

Two novel series 2a–2d (2Z)-N-[5-(4-substituted)phenyl-1,3,4-oxadiazol-2-yl]-2-[(2Z)-3,7-dimethylocta-2,6-dien-1-ylidene]hydrazinecarboxamide and 1a–1d 5-(4-substituted)phenyl-N-[(1Z,2Z)-3,7-dimethylocta-2,6-dien-1-ylidene]-1,3,4-oxadiazol-2-amine have been synthesized and screened for their anticonvulsant and neurotoxic activity. After i.p. injection to mice at doses of 30, 100 and 300 mg/kg body weight 2,5-disubstituted-1,3,4-oxadiazole analogues were examined in the maximal electroshock induced seizures (MES) and subcutaneous metrazole (ScMET) induced seizure models in mice. Amongst all the compounds, 1a–1d and 2a–2d, one compound 1a exhibited activity at 100 mg/kg body weight at 0.5 and 4 h in ScMET, respectively. Compound 2b showed anticonvulsant activity at 100 mg/kg without activity in ScMET and neurotoxicity. The neurotoxicity was assessed by rotorod method, and all compounds (except 1a) were found to be safe at maximum administered dose.     

3,5-Disubstituted thiadiazine-2-thiones: New cell-cycle inhibitors

Two series, a and b, of 3-cyclopentyl or (3-cyclohexyl)-5-substituted-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazine-2-thiones (THTT) 2a–9a and 3b, 4b, 6b–9b, were synthesized to develop new cell cycle inhibitors. Variable and promising in vitro antiproliferative activities were shown with the synthesized THTT derivatives. Compound 5a with a 5-cyclopentyl group on position-3 and a glutamine residue on position-5 of the THTT moiety showed maximum activity (IC₅₀ = 8.98 μM). Compound 5a possessed notable cell cycle disrupting and apoptotic activities with enhanced selectivity against cancer cells, suggesting the potential for the development of new selective cell cycle inhibitors. There is no evident relationship between the cytotoxic activity of the tested compounds and their lipophilicity. In addition, a pharmacophore based study was performed to explain the biological activity on structural bases. A successful model was generated with a good correlation with the observed activity.