Synthesis,antimicrobial, and antioxidant activity of benzofuran barbitone and benzofuran thiobarbitone derivatives

The synthesis of novel series of benzofuran derivatives, containing barbitone moiety, 5-[(2/4-substitutedphenyl)(5-substituted-1-benzofuran-2-yl) methylidene]pyrimidin-2,4,6(1H,3H,5H)-trione (4a–i) and thiobarbitone moiety, 5-[(2/4-substitutedphenyl)(5-substituted-1-benzofuran-2-yl)methylidene]-2-thioxodihydropyrimidin-4,6(1H, 5H)-dione (5a–i) have been reported. The target compounds (4a–i) and (5a–i) were synthesized by the Knoevenagel condensation of (5-substituted-1-benzofuran-2-yl)(2/4-substitutedphenyl) methanone (3a–i) with barbituric acid and thiobarbituric acid, respectively, in acid medium. These compounds were screened for the antimicrobial and antioxidant activities. From antimicrobial activity results it was found that compounds 4a, 5a, 4c, and 5c displayed good antibacterial and antifungal activity against all tested strains. Further, the synthesized compounds were studied for docking on the enzyme, Glucosamine-6-phosphate synthase and the compounds 4c and 5c have emerged has an active antimicrobial agent with least binding energy (?5.27 and ?4.85 kJ mol^?1). Compounds 4e, 4f, 5e, and 5f showed promising free radical scavenging activity and compounds 5a and 5b showed good chelating ability with Fe²⁺ ions.     

Synthesis, biological evaluation, and molecular modeling studies of novel heterocyclic compounds as anti-proliferative agents

Two novel series of heterocyclic compounds have been synthesized. In first series, isatin was allowed to react with substituted aromatic/cyclic carbonyl compounds to get desired mannich bases (2a–e). In second series, 4,5-disubstituted oxazoles (6a–p) were synthesized. Eight compounds (2c, 6a, 6e, 6f, 6i, 6j, 6m, and 6n) were screened for anticancer activity in 60 cell lines. Compound 2c, 1-[(4,7,7-trimethyl-3-oxobicyclo[2.2.1]heptan-2-yl)methyl]indoline-2,3-dione, showed maximum activity and thus, selected for further evaluation at five dose level screening. Furthermore, molecular docking studies of compounds 2c into the colchicine-binding site of tubulin, revealed possible mode of inhibition by the compound.     

Synthesis of β-amino carbonyl derivatives of coumarin and benzofuran and evaluation of their biological activity

A series of β-amino carbonyl compounds containing coumarin (4a–h) and benzofuran (6a–i) moieties was synthesized by a three component Mannich reaction of 3-acetyl-2H-chromen-2-one (1) or 1-(1-benzofuran-2-yl) ethanone (5) with p-substituted aromatic aldehydes (2a–g) and aromatic amines (3a–b) in the presence of cerric ammonium nitrate as a catalyst. The newly synthesized compounds were screened for antimicrobial and antioxidant activities. Compounds 4b, 4e, 4f, 6f, 6g, and 6i showed microbial inhibition with minimal inhibition concentration ranging between 0.040 and 0.500 mg/mL, compounds 4b, 4c, 6c, 6e, and 6i showed promising free radical scavenging activity and compounds 4b, 4f, 6c, 6d, and 6h showed good chelating ability with Fe²⁺ ions. The synthesized compounds were studied for docking on the enzyme, glucosamine-6-phosphate synthase to predict the binding affinity and orientation at the active site of the receptor.     

Synthesis, antitumor activity of 2-amino-4H-benzo[h]chromene derivatives, and structure–activity relationships of the 3- and 4-positions

Several 2-amino-4H-benzo[h]chromenes (3a–i) and (5a–h) were obtained by reaction of 4-chloro-1-naphthol (1) with α-cyanocinnamonitrile (2a–i) or ethyl α-cyanocinnamate derivatives (4a–h), respectively. Structures of these compounds were established on the basis of spectral data. The antitumor activity of the synthesized compounds was investigated in comparison with Vinblastine, Colchicine, and Doxorubicin well-known anticancer drugs, using MTT colorimetric assay. Among them, the compounds 5e, 3c, 5f, b, d, 3d, 5c, a were the most active against MCF-7, 5a against HCT-116 and 5a, 3e, a against HepG-2 as compared with the standard drug Vinblastine, while the compounds 5e, 3c, 5f, b, d, 3d, 5c, a, h, 3i, g, a, e were the most active against MCF-7, 5a, c, e, f, b, 3e, c, g, b, 5d, h, 3d, i, 5g against HCT-116, 5a, 3e, a, 5e, 3c, 5d, c, f, 3b, 5g, 3g, 5h against HepG-2 as compared with the standard drug Colchicine. The structure–activity relationships of the 3- and 4-positions were discussed.     

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 of some novel C-5 and N-3 substituted 2-(2-hydroxyphenylimino)thiazolidin-4-one derivatives with broad-spectrum antimicrobial activity

In the present article, compounds 5-((substituted-2-chloroquinolin-3-yl)methylene)-2-(2-hydroxyphenylimino)thiazolidin-4-ones (3a–k), 1-(2-(2-(2-hydroxyphenylimino)-4-oxothiazolidin-3-yl)-2-oxoethyl)pyrimidine-2,4,6(1H,3H,5H)-trione (6) and 1-(2-(5-((substituted-2-chloroquinolin-3-yl)methylene)-2-(2-hydroxyphenylimino)-4-oxothiazolidin-3-yl)-2-oxoethyl)pyrimidine-2,4,6(1H,3H,5H)-triones (8a–k) have been synthesized by substituting C-5 and N-3 position of parent compound 2-(2-hydroxyphenylimino)thiazolidin-4-one (1). Structures of the newly synthesized compounds were assigned on the basis of elemental analyses, IR, ¹H NMR, ¹³C NMR, and mass spectra. In vitro antimicrobial activity of target compounds (3a–k, 6 and 8a–k) was investigated against two Gram-positive, two Gram-negative bacteria and three fungal strains. Among the tested compounds (3e), (3f), and (3h) showed very good antifungal activity, while compound (6) showed very good antibacterial activity. Compounds (8e), (8f), and (8h) showed excellent antifungal and antibacterial activities.     

5-phenyl-1-benzofuran-2-yl derivatives: synthesis, antimicrobial, and antioxidant activity

Previously unknown biphenyl containing 5-phenyl-1-benzofuran-2-yl derivatives; methanones (2a–i), tertiary alcohols (3a–l), and carbinols (4a–f) were synthesized and evaluated for their antimicrobial and antioxidant activities to study the effect of functionalization at the carbonyl carbon and substitution at biphenyl ring on these activities. The introduction of hydroxyl group at carbonyl carbon enhanced the antioxidant property (3a, 3g, 3h, 4a, and 4b), while antimicrobial activity decreased; the carbinol and tertiary alcohols corresponding to methanone 2a and 2b showed no antimicrobial activity. Biphenyl methanones 1, 2a, 2f, and 2g exhibited antimicrobial activity with minimal inhibitory concentration ranging between 0.001 and 0.500 mg/mL, tertiary alcohols 3a, 3g, and 3h and carbinols 4a and 4b exhibited the promising antioxidant property. The mode of action of these active compounds was carried out by docking of receptor GlcN6P synthase with newly synthesized candidate ligands 1, 2a, 2e, 2f, 2g, 2h, 3a, 3g, 3h, 4c, and 4d.     

Synthesis and antiprotozoal activity of 1,2,3,4-tetrahydro-2-thioxopyrimidine analogs of combretastatin A-4

Eighteen 1,2,3,4-tetrahydro-2-thioxopyrimidine analogs (5a?Cj, 6a?Ce, and 7a?Cc) of combretastatin A-4 were synthesized with the objective of discovering compounds capable of controlling the growth of Trypanosoma?lewisii, Leishmania?tarantole, Plasmodium?falciparum, and Giardia?lamblia. Even though the target compounds demonstrated differential cytotoxicity against mammalian cancer cells, with IC₅₀ values ranging from 0.5 to >100???M, the range of activity against Trypanosoma, Leishmania, and Plasmodium, and to a good extent for Giardia, was narrow. The IC₅₀ values of ??active?? compounds against the parasites ranged from about 10???? to slightly greater than 50???M. Specifically, compounds 5a, 5g, 5h, 6c, 7a, and 7c were not cytotoxic against mammalian cancer cells (IC₅₀?>?100???M) but showed good activity against the parasites, except Giardia (e.g., compounds 6c and 7a), suggesting that these compounds may act in a similar mechanism in parasites. Compounds 5f and 6b were previously shown to promote microtubule depolymerization in mammalian cells.     

Synthesis, anti-inflammatory, and cytotoxicity evaluation of 9,10-dihydroanthracene-9,10-α,β-succinimide and bis-succinimide derivatives

9,10-Dihydroanthracene-9,10-α,β-succinimide derivatives 4a–e and bis-succinimide derivatives 6a–e have been synthesized by grinding 9,10-dihydroanthracene-9,10-α,β-succinic anhydride 2 with various mono 3a–e and diamines 5a–e in quantitative yields. All the target compounds were fully characterized by spectrometric and spectroscopic means. Compounds 4a–e, 6a–e and recently reported compounds 4f–p were screened for anti-inflammatory and for cytotoxicity against five human cancer cell lines: T47D, NCI H-522, HCT-15, PA1, and HepG-2. Compounds 4e, 4i, 4j, and 4p exhibited good anti-inflammatory activity and compounds with interesting cytotoxic profile were 4c, 6e (T47D); 4e, 4o (NCI H-522); 4n (HCT-15); 4e, 4h, 4o (PA1); and 4a, 4e, 4f, 4i, 4o (HepG-2).     

Synthesis, characterization and antimicrobial studies of a few novel thiazole derivatives

A series of novel N-[4-(substituted)-1,3-thiazol-2-yl]-2-(substituted)acetamide (9a–m) and methyl 2-(2-(2-(substituted)acetamido)thiazol-4-yl)acetate (9n–o) derivatives have been synthesized and compounds were characterised by spectral and analytical studies. All compounds were screened for their in vitro antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia by disc diffusion method and for antifungal activity against Penicillium marneffei, Trichophyton mentagrophytes, Aspergillus flavus and Aspergillus fumigatus by serial plate dilution method. Compounds 9b, 9e, 9m and 9o exhibited growth inhibition against all the tested bacterial strains, with MIC values varying from 12.5 to 6.25 μg/ml. Among the compounds tested for antifungal activity, 9a, 9b, 9d, 9j, 9k, 9p and 9n showed wide range of activity against all the tested strains. Most of the newly synthesized compounds were effective against fungal strains rather than bacterial strains. However, some of the compounds like 9a, 9e, 9j, 9k and 9i showed selective sensitivity against some of the bacterial strains whereas they were unable to sustain the growth of other strains.     

Efficient synthesis of piperazine-2,6-dione and 4-(1H-indole-2-carbonyl)piperazine-2,6-dione derivatives and their evaluation for anticancer activity

Condensation of iminodiacetic acid 1 with various amines i.e., cyclohexanamine, 1-(3-aminopropyl)imidazole, pyridin-2-ylmethanamine, pyridin-3-ylmethanamine, pyridin-4-ylmethanamine, 2-morpholinoethanamine, thiophen-2-ylmethanamine, 2-(thiophen-2-yl)ethanamine, furan-2-ylmethanamine, 2-(pyrrolidin-1-yl)ethanamine, and 1-(3-aminopropyl) pyrrolidin-2-one 2a–k under microwave irradiation gave the corresponding piperazine-2,6-dione derivatives 3a–k in quantitative yields. Piperazine-2,6-dione derivatives 3a–k on condensation with 1H-indole-2-carboxylic acid under microwave irradiation gave the corresponding 4-(1H-indole-2-carbonyl)piperazine-2,6-dione derivatives 4a–k in quantitative yields. All the synthesized compounds (3a–k & 4a–k) were purified by crystallization and characterized by spectroscopic means. On screening at a concentration of 10 μM, compounds 3k, 4e, 4i breast (T47D), 4j lung (NCI H-522), 3i colon (HCT-15), 4e ovary (PA-1), and 4g liver (HepG-2) exhibited good anticancer activity.     

Synthesis, antitumor activity, and structure–activity relationship of some 4H-pyrano[3,2-h]quinoline and 7H-pyrimido[4′,5′:6,5]pyrano[3,2-h]quinoline derivatives

Several 4H-pyrano[3,2-h]quinoline (3a–d, 4a, 7a,b, 9a–c, 10a,b, 11a,b, and 13a–c) and 7H-pyrimido[4′,5′:6,5]pyrano[3,2-h]quinoline derivatives (8a–c) were obtained by treatment of 8-hydroxyquinoline (1a) and 8-hydroxy-2-methylquinoline (1b) with α-cyano-p-chloro/bromocinnamonitrile (2a,b) or 4H-pyrano[3,2-h]quinoline derivatives (3a,c,d) with different electrophilic reagents followed by nucleophilic reagents. Structures of these compounds were established on the basis of spectral data. The antitumor activity of the synthesized compounds was investigated in comparison with Vinblastine. Among them, compounds 3c,d, 4a, 8b, 9b,c, 11a,b, and 13a,c inhibited the growth of cancer cells compared to Vinblastine. The structure–activity relationships were discussed.     

Synthesis of new oxadiazole derivatives as anti-inflammatory, analgesic, and antimicrobial agents

In search of pharmalogically active molecules in the class of oxadiazoles, the present article deals with the synthesis of 5-(5′-fluoro-2′-methoxybiphenyl-3-yl)-1,3,4-oxadiazol-2(3H)-one 2 from its hydrazide analog 1. The compound 2 was regioselectively N-alkylated with alkyl halides and produced the compounds 3a–f. Compound 3f was further functionalized with substituted benzenesulfonyl chlorides to give compounds 3g–j. The synthesized compounds were characterized by elemental and spectral analysis. Newly synthesized compounds were tested for their in vivo anti-inflammatory, analgesic, and in vitro antimicrobial activities. The compounds 3a–c were found to have promising anti-inflammatory and analgesic activities. Compounds 3b, 3f, and 3g showed significant antibacterial and antifungal activities.     

Synthesis, characterization, and antimicrobial screening of some Mannich base sydnone derivatives

The title compounds (5a–j), (6a–j), and (7a–j) were prepared via a four-step procedure using starting material 4-methoxyaniline (1). The structure of all synthesized compounds was confirmed by FT-IR, ¹H NMR, ¹³C NMR, and CHN analysis. The synthesized compounds were tested for their antibacterial and antifungal activity (MIC) in vitro against organisms viz. B. subtilis, S. aureus, E. coli, P. aeruginosa, and C. albicans taking ciprofloxacin, ampicillin, streptomycin, penicillin-G, fluconazole, and nystatin as the standard drugs. Some of the compounds have shown significant activities.     

Synthesis of some new indolo[2,3-c]isoquinolinyl pyrazoles, -1,3,4-oxadiazoles and their biological activities

A new series of novel compounds [10-substituted 6H, 7H-indolo[2,3-c]isoquinolin-5-one-6-yl]carbohydrazides (3a–c), 1-[10-substituted 6H, 7H-indolo[2,3-c]isoquinolin-5-one-6-yl]fomyl-, -3′,5′-dimethylpyrazoles (4a–c), -3′,5′-diphenylpyrazoles (5a–c), -3′-methylpyrazol-5′-ones (6a–c) and -1′,3′,4′-oxidiazole-2′-thiones (7a–c) linked to indoloisoquinoline at position-6 through formyl bridge was prepared. The structures of these newly synthesized compounds were confirmed by their spectral studies and elemental analysis. These compounds have been screened for their antimicrobial and antioxidant activities. Compounds 4a, 4b, 5a, 5b, 5c, 6b, 7a, and 7c exhibited the maximum zone of inhibition against A. niger, A. flavus, and A. fumigatus. Compounds 4a, 5a, 5c, 6b, 6c, 7a, and 7b showed good antibacterial activity. Compounds 4b, 4c, 5b, 5c, 6a, 6b, 7a, 7b, and 7c showed good radical scavenging activity compared with standards.     

New 4-thiazolidinones from 5-ethyl pyridine-2-ethanol: their antibacterial,antifungal, and antitubercular activity

New thiazolidinones 5a–o were prepared from Schiff base 4a–o and thioglycolic acid in the presence of ZnCl₂ from 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR ¹³C NMR, and mass spectral data. All the compounds were screened against different strains of bacteria and fungi. Compounds 4e, 4n, 4m, 4o, 5e, 5f, 5j, and 5m possessed very good activity against bacterial and fungal species. These active compounds impelled us to study their antitubercular activity. Schiff base 4n and 4e showed M. tuberculosis MIC value 25 and 62.5 μg/ml, respectively. Thiazolidinone 5m displayed M. tuberculosis MIC at 25 μg/ml, which is better antitubercular activity compared with rifampicin.     

Synthesis,antimicrobial and cytotoxic activity of 2-azetidinone derivatives of pyridyl benzimidazoles

In the present study, a series of novel 6-(1H-benzo[d]imidazol-2-yl)-2-(3-chloro-2-oxo-4-phenylazetidin-1-yl)-4-(aryl)nicotinonitriles 6a–o were efficiently synthesized and evaluated for their in vitro antibacterial activity against Gram-positive (Staphylococcus aureus and Streptococcus pyogenes), Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and fungal (Candida albicans, Aspergillus niger and Aspergillus clavatus) strains. The results of antimicrobial study revealed that compounds 6b, 6c, 6d, 6h and 6i exhibited substantial antibacterial activity while compounds 6c and 6h emerged as the most potent antifungal agents compared to the standard drugs chloramphenicol and ketoconazole, respectively. From the standpoint of SAR studies, it was observed that the presence of electron-withdrawing groups remarkably enhances the antibacterial activity of newly synthesized compounds. Further, the results of preliminary MTT cytotoxicity studies on HeLa cells suggested that potent antimicrobial activity of 6b, 6c, 6d, 6h and 6i is accompanied by low level of cytotoxic concentrations. All the newly synthesized analogues were characterized by IR, ¹H NMR, ¹³C NMR and mass spectral data.     

Synthesis, characterization, and SAR studies of new (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide derivatives as possible antimicrobial and antitubercular agents

In this article, we report herein the SAR studies of a series of (1H-indol-3-yl)alkyl-3-(1H-indol-3-yl)propanamide 10(a–j), 11(a–j). The synthesized compounds were evaluated for their preliminary in vitro antibacterial, antifungal activity and were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The synthesized compounds displayed interesting antimicrobial activity.     

Synthesis of azabicyclo[4.2.0]octa-1,3,5-trien-8-one analogues of 1H-imidazo[4,5-c]quinoline and evaluation of their antimicrobial and anticancer activities

In search of new and efficient antimicrobial and anticancer agents based on the imidazoquinoline structural framework, a series of novel 7-(1-isobutyl-1H-imidazo[4,5-c]quinolin-4-yl)-7-azabicyclo[4.2.0]octa-1,3,5-trien-8-ones (8a–f) were synthesized from the corresponding 2,4-dihydroxoquinoline derivative through multistep reactions. The structures of these compounds were established by IR, ¹H NMR, ¹³C NMR and mass spectral studies. The 7-(1-isobutyl-1H-imidazo[4,5-c]quinolin-4-yl)-7-azabicyclo[4.2.0]octa-1,3,5-trien-8-one (8a–f) analogues were evaluated for their in vitro antimicrobial activity by serial dilution method minimum inhibitory concentration (MIC). The derivatives 8c, 8e and 8f exhibited excellent antibacterial activity comparable to the parent drug ampicillin with MIC value. Compounds 7a–f and 8a–f were also assessed for their cytotoxic activity (IC₅₀) against HeLa cells using the Trypan blue exclusion assay method. The compounds 7c and 8b displayed potential anticancer activity. In a molecular docking study, these compounds showed minimum binding energy and good affinity towards the active pocket. They are believed to be good inhibitors of β-tubulin. The results of these studies provided evidence that 7-(1-isobutyl-1H-imidazo[4,5-c]quinolin-4-yl)-7-azabicyclo[4.2.0]octa-1,3,5-trien-8-one (8a–f) derivatives are a promising class of antibacterial and anticancer agents.