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.     

Design and evaluation of new hybrid pharmacophore quinazolino-tetrazoles as anticonvulsant strategy

The anticonvulsant study of 25 newly synthesized quinazolin-4(3H)-one substituted 1H and 2H-tetrazoles (6a–6d, 7a–7b, 8a–8i, 8a′–8i′) was executed. The study employing the maximal electroshock and subcutaneous pentylenetetrazole (scPTZ) screens, the ‘gold standards’ in the preliminary anticonvulsant breakthrough and the neurotoxicity study applying the rotorod test unveiled a triad of compounds 6c, 7b and 8i′ as the looms amongst the compendium of synthesized compounds. The quantification data of these compounds following oral administration in rats showcased 7b to endorse a remarkable position in the MES screen with a protective indice (PI) of >39.67 and 6c in the scPTZ delineating a PI > 3.10, respectively. All the potent compounds were destitute of toxicity.     

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.     

Heteroaromatic analogues of 1,5-diarylpyrazole class as anti-inflammatory agents

A novel series of heteroaromatic analogues of known anti-inflammatory (AI) drug celecoxib replacing the benzenesulfonamide moiety with 6-sulfonamidobenzothiazol-2-yl moiety was synthesized. Regioselective synthesis of the target compounds 2a–i having 1,5-diaryl relationship was achieved by exploring reaction conditions. All the newly synthesized compounds (2a–i and 8) were screened for their in vivo AI activity using carrageenan-induced rat paw edema assay. Five compounds (2c–f and 2i) were found to possess good AI activity (≥60% inhibition), 3?h after the carrageenan injection when compared to that of standard drug indomethacin (78%), whereas the remaining four compounds (2a–b and 2g–h) with 1,5-diaryl relationship have shown moderate activity with 49–56% inhibition after 3?h. However, pyrazole 8 having 1,3-diaryl relationship failed to show appreciable AI 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, 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,antimicrobial, and cytotoxic activities of novel benzimidazole derivatives bearing cyanopyridine and 4-thiazolidinone motifs

A series of 6-(1H-benzo[d]imidazol-2-yl)-2-(2-(3-nitrophenyl)-4-oxothiazolidin-yl)-4-(aryl)nicotinonitriles 5a–l were synthesized and characterized by IR, ¹H NMR, ¹³C NMR, and mass spectrometry techniques. These novel compounds 5a–l were screened for their in vitro antimicrobial activity against different bacterial and fungal strains and in vitro cytotoxicity study (HeLa cell line) using MTT colorimetric assay. The results demonstrated that compounds 5c, 5e, and 5i–k exhibited excellent antibacterial activity, while compounds 5d, 5i, and 5k were found to be the most potent antifungal agents. From the standpoint of SAR studies, it was observed that the presence of electron donating groups remarkably enhanced the antimicrobial activity of newly synthesized compounds. Further, the results of preliminary MTT cytotoxicity studies on HeLa cells suggested that potent antimicrobial activity of 5c–e and 5i–k was accompanied by low cytotoxicity.     

Synthesis of benzothiazole derivatives having acetamido and carbothioamido pharmacophore as anticonvulsant agents

A new series of N-(6-chlorobenzothiazol-2-yl)-2-substituted-acetamides (3a–h) and N-(6-chlorobenzothiazol-2-yl)-2-(substituted-benzylidene)hydrazinecarbothioamides (5a–h) were synthesized and characterized by IR, ¹H NMR, mass and elemental analysis. In vivo anticonvulsant and acute toxicity screening of all the synthesized compounds showed morpholino (3f) and imidazolyl (3g) derivatives as promising anticonvulsant lead. Furthermore, In silico drug-likeness parameters have also been investigated for filtering out the likelihood of poor drug absorption or brain penetration. 3D four-point pharmacophore measurements of compounds were also carried out to match these with established anticonvulsants agents.     

Synthesis and evaluation of anti-proliferative activity of 1,4-disubstituted phthalazines

A series of new phthalazine derivatives 3a–i and 4a–c were synthesized via the reaction of 1-chlorophthalazine derivative 2 with either N-substituted-piperazines, primary or their secondary amines. The structure of the synthesized, new compounds were characterized by spectral data. The anti-proliferative activity on human breast cancer cell line MCF-7 of the synthesized compounds was determined. The results showed that six of the test compounds (3a, 3g, 3i, and 4a–c) displayed potent cytotoxic activity ranging from 1.4 to 2.3?μmol.     

Synthesis,characterization, and antibacterial activities of some novel N,N′-disubstituted thiourea, 2-amino thiazole,and imidazole-2-thione derivatives

In the search of bioactive molecules, a series of novel N-substituted thiourea derivatives 3(a–d) are prepared by reaction of the α-amino pyridyl ketone hydrochloride (2a) with the corresponding aryl isothiocyanates. The synthesis of some new 2-amino thiazoles 4(a–d) and imidazole-2-thiones 6(a–d) were attempted by intramolecular cyclization reaction of the N,N′-disubstituted thioureas 3(a–d) and their intermediate ketals 5(a–d) in diluted aqueous acidic and strong acidic mediums. The structure of all newly synthesized compounds was established by analytical and spectral data. The antibacterial studies to all of the synthesized compounds against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis bacteria with Gram-positive and negative strains, as MIC values are reported. Some of these compounds such as 3a,b,d and 4b,d exhibited a good to significant antibacterial activity. Also, all of new synthesized compounds 3,4,6(a–d) were active against Gram-positive S. aureus bacterium. Thus, some of these compounds can emerge as a promising tool for further research work.     

Synthesis and biological activity of novel Schiff bases derived from metronidazole

A number of novel Schiff bases (5a–i) and (7a–d) derived from metronidazole were synthesized. Reaction of 2-(2-methyl-5-nitro-imidazol-1-yl)-ethyl ester toluene-4-sulfonate with 4-hydroxybenzaldehyde and with 3-hydroxybenzaldehyde in the presence of a base afforded 4-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethoxy)benzaldehyde (5) and 3-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethoxy)benzaldehyde (7), respectively. The reaction of aldehydes 5 and 7 with a number of primary aromatic amines produced Schiff bases 5a–i and 7a–d, respectively. Structures of these compounds were confirmed through different spectroscopic methods such as ¹H-NMR, ¹³C-NMR, mass spectrometry, and also by elemental analyses. The prepared compounds were evaluated in vitro for their antigiardial, anti-trichomonal, antibacterial, and antifungal activities. Compounds 5e, 5g, 5i, 7a, 7b, 7c, and 7d exhibited remarkable antigiardial activity and were found to be more active than metronidazole with IC₅₀ of 7.2, 3.3, 1.5, 5.8, 4.5, 2.9, and 3.8 µg/mL, respectively. Compounds 5a and 5c also exhibited antigiradial activity with similar IC₅₀ values compared to the reference drug metronidazole with IC₅₀ of 7.2 µg/mL. The other compounds 5b, 5d, 5f, and 5 h also showed antigiardial activity but with higher IC₅₀ compared to the reference drug. Compounds were also tested for their anti-trichomonal activity, they, however, exhibited higher IC₅₀ compared to the reference drug metronidazole (7.4 µg/mL), except for compound 5a which exhibited anti-trichomonal activity with an IC₅₀ of 6.3 µg/mL. On the bases of preliminary screening, the newly synthesized compounds exhibited moderate to potent antimicrobial activities. Compound 5e inhibited the growth of Methicillin resistant Staphylococcus aureus (MRSA) and Bacillus cereus and compound 5c inhibited Candida Pathogenic fungus at 50 μg/mL compared with the positive control (Nystatin) which inhibits Candida at 25 μg/mL.     

Novel 2-(E)-substituted benzylidene-6-(N-substituted aminomethyl)cyclohexanones and cyclohexanols as analgesic and anti-inflammatory agents

Twenty-two new 2-(E)-substituted benzylidene-6-(N-substituted aminomethyl)cyclohexanones (6a–6j) and cyclohexanols (7a–7l) were designed and synthesized. Target compounds were obtained through Stork enamine, Mannich, and Grignard reactions taking cyclohexanone as starting material. The structures were confirmed by the application of IR, ¹H NMR, MS, and HR-MS data. The analgesic activities were evaluated by acetic acid-induced writhing test and hot plate method. The anti-inflammatory activities were assayed by xylene-induced ear swelling and carrageenan-induced paw edema in mice model. All tested compounds showed analgesic and anti-inflammatory capacities in oral administration. Some compounds (6a, 6c, 6h, 6i, 7c, 7h, and 7i) displayed the moderate analgesic activity compared with positive control ibuprofen, and some compounds (6a, 6b, 6d, 6h, 7a, and 7d) exhibited more anti-inflammatory activity than ibuprofen. Among them, compound 6a could be a potential nonsteroidal anti-inflammatory agent with significant analgesic activities and remarkable anti-inflammatory activities. Further research is being conducted.     

Synthesis, anti-inflammatory and anticancer activity evaluation of some mono- and bis-Schiff’s bases

Several mono-Schiff’s bases (3a–i) and bis-Schiff’s bases (5a–f) were synthesized using microwave irradiation technique (3a–h, 5a–c) and by simply grinding at room temperature for a few minutes (3i, 5d–f). All these compounds were characterized by spectroscopic means and elemental analysis. They were screened for anti-inflammatory and anticancer activities (against five human cancer cell lines). Compound 5f exhibited good anti-inflammatory and compounds 3f, 5a–f exhibited good anticancer activity.     

Synthesis, physicochemical properties, antimicrobial and antioxidant studies of pyrazoline derivatives bearing a pyridyl moiety

A series of new pyrazoline compounds bearing a pyridyl moiety (4a–i) were synthesized by condensing appropriate chalcones with hydrazine hydrate and tested for antimicrobial and antioxidant activities. According to in vitro antimicrobial activity against Bacillus subtilis, Staphylococcus epidermidis, Proteus vulgaris, Pseudomonas aeruginosa, Aspergillus niger and Penicillium chrysogenum and antioxidant activity by DPPH method, the compounds 4a, 4d, 4i and 4e, 4f, 4h showed maximum antimicrobial and antioxidant activities, respectively. Physiochemical properties and Lipinski’s ‘Rule of Five’ analysis predicted higher intrinsic quality of the synthesized compounds and revealed that these compounds have good bioavailability and druglikeness properties.     

Synthesis and pharmacological evaluation of some novel 2-pyrazolines bearing benzenesulfonamide as anti-inflammatory and blood glucose lowering agents

A series of novel pyrazolines (2a–l) bearing benzenesulfonamide moiety were synthesized by condensing appropriate chalcone (1a–l) with 4-hydrazinobenzenesulfonamide hydrochloride. Structure of all novel synthesized compounds was characterized on basis of elemental analysis data and spectral data (IR, ¹HNMR, MS). Compounds (2a–l) were screened for in vivo anti-inflammatory action in carrageenan-induced rat paw edema model and blood glucose lowering action in glucose fed hyperglycemic normal rats. Compounds 2a, 2e, and 2l showed significant anti-inflammatory action (more than 75 %) at 5 h and also showed superior gastrointestinal safety profiles as compared to celecoxib. One compound (2i) was found to exhibit significant blood glucose lowering activity.     

Synthesis, antioxidant, and antibacterial studies of phenolic esters and amides of 2-(1-benzofuran-2-yl) quinoline-4-carboxylic acid

A new series of phenolic esters 2(a–j) and amides 3(a–c) of 2-(1-benzofuran-2-yl) quinoline-4-carboxylic acid were synthesized by the reaction of 2-(1-benzofuran-2-yl)-quinoline-4-carboxylic acid (1) with various substituted phenols and secondary amines using ethyl-(N′,N′-dimethylamino)propyl carbodiimide hydrochloride (EDC.HCl) as a coupling agent. The newly synthesized compounds were evaluated for in vitro antioxidant and antibacterial activity. Among all tested compounds 2a, 2c, 2e, and 2h showed good chelating ability with Fe⁺² ions, whereas compounds 2g and 2j exhibited good scavenging activity with DPPH free radicals. Concerning antibacterial activities compounds 2a, 2b, 2c, and 2h were found to be equipotent to ampicillin against Enterococcus sp and Staphylococcus aureus, while compound 2e is found to be as potent as ampicillin against Pantoea Dispersa and Ochrobactrum sp. amide derivatives 3(a–c) were found to be less potent when compared to standard.     

Synthesis, characterization, and in vitro antimicrobial evaluation of new 5-chloro-8-bromo-3-aryl-1,2,4-triazolo[4,3-c]pyrimidines

A series of new 5-chloro-8-bromo-3-aryl-1,2,4-triazolo[4,3-c]pyrimidines (4a–j) have been accomplished in excellent yields by the oxidative cyclization of pyrimidinylhydrazines (3a–j) of various aryl aldehydes with one equivalents of iodobenzene diacetate in methanol. The chemical structures of the synthesized compounds were confirmed by elemental analyses, FT-IR, ¹H NMR, ¹³C NMR, and mass spectral studies. Ten new compounds (4a–j) were tested in vitro for their antimicrobial activity against clinically isolated strains. Variable and modest activities were observed against the investigated strains of bacteria and fungi. Compounds 4f, 4i, and 4j demonstrated good antimicrobial activity against all the tested microbial strains.     

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.     

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.     

New thiazolidine-2,4-diones as antimicrobial and cytotoxic agent

New (Z)-5-substituted-2,4-thiazolidinediones (3a–m) were easily prepared by the condensation of thiazolidine-2,4-dione (1) with suitable aldehydes (2a–m) via microwave irradiation technique. The reaction between (Z)-5-substituted-2,4-thiazolidinediones and 4-(bromomethyl) benzoic acid, using potassium carbonate as base in refluxing acetone, followed by a workup in acidic medium provided 4-(((Z)-5-substituted-2,4-dioxothiazolidin-3-yl)methyl) benzoic acid derivatives (4a–m). The structures of the newly synthesized compounds were confirmed by IR, ¹H NMR, ¹³C NMR spectral studies, and elemental analysis. All compounds were evaluated for their in vitro antimicrobial and cytotoxic activities. Antibacterial and antifungal results revealed that most of the compounds showed significant activity where as compounds 4c and 4g are found to be broad spectrum antibacterial and antifungal properties, the MIC values were observed in the range of 2–4 and 2–8?μg/ml, respectively. In MTT cytotoxicity studies, the compound 4g was found most potent. In HeLa, HT29, A549, and MCF-7 cells, the IC₅₀ values were observed in the range of 30–36?μM.