A series of 4-(2-fluorophenoxy)quinoline derivatives bearing the 4-oxo-1,4-dihydroquinoline-3-carboxamide moiety were designed, synthesized, and evaluated for their in vitro antitumor activity against the H460, HT-29, MKN-45, U87MG, and SMMC-7721 cancer cell lines. Most of the tested compounds showed potent activity and high selectivity toward the HT-29 and MKN-45 cell lines. Furthermore, compounds 21b, 21c, and 21i were further examined for their c-Met kinase activity and exhibited strong efficacy with IC₅₀ values in the single-digit nanomolar range, which was comparable with the positive control foretinib. The most promising compound 21c showed excellent cytostatic activity with IC₅₀ values from 0.01 to 0.53 µM against all tested cell lines, thus being 1.7–2.2 times more active than foretinib.

Novel 4-(2-fluorophenoxy)quinoline derivatives bearing the 4-oxo-1,4-dihydroquinoline-3-carboxamide moiety were evaluated for their in vitro antitumor activity against several cancer cell lines. Compounds 21b, 21c, and 21i were also examined for their c-Met kinase activity in comparison to foretinib. Compound 21c showed excellent cytostatic activity with IC₅₀ values from 0.01 to 0.53 µM against all tested cell lines and higher activity than foretinib.

(E)-4-Aryl-2-[2-(1-substituted ethylidene)hydrazinyl]thiazoles and (Z)-3-substituted-4-aryl-2-[(E)-(1-phenylethylidene)hydrazono]-2,3-dihydrothiazoles were synthesized by the reaction of (substituted ethylidene)hydrazinecarbothioamides with ω-bromoacetophenones. The characterization of this new class of compounds was performed using different spectroscopic tools. The structure of (Z)-3-benzyl-4-(4-bromophenyl)-2-[(E)-(1-phenylethylidene)hydrazono]-2,3-dihydrothiazole 6e was unambiguously confirmed by single-crystal X-ray crystallography. Compounds 5a–e, 5i, 6e, 6g, and 6i were screened for their in vitro antibacterial activity against different strains of microorganisms; most of the tested compounds exhibited promising antibacterial activity against some organisms compared to ciprofloxacin and sulbactam penicillin. Compounds 5e, 5i, 6e, 6g, and 6i exhibited several-fold significant antibacterial activity against the Gram-positive bacteria Staphylococcus aureus, better than ciprofloxacin, with minimum inhibitory concentration values ranging from 0.05 to 0.4 µg/mL. The rest of the tested compounds gave significant antibacterial activities against different Gram-negative bacterial strains.

Ethylidenehydrazinylthiazoles and ethylidenehydrazono-2,3-dihydrothiazoles were synthesized by cyclization of ethylidenehydrazinecarbothioamides. The structure of (Z)-3-benzyl-4-(4-bromophenyl)-2-[(E)-(1-phenylethylidene)hydrazono]-2,3-dihydrothiazole 6e was unambiguously confirmed by single-crystal X-ray crystallography. The synthesized compounds were screened for their in vitro antibacterial activity against different strains of microorganisms.

A new series of benzothiazoles and benzoxazoles was synthesized using 4-benzothiazol-2-yl-phenylamine and 4-benzoxazol-2-yl-phenylamine as starting materials. All the prepared compounds were evaluated for their antitumor activities against human breast cancer cell lines, MCF-7 and MDA-231, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability analysis. Almost all the tested compounds revealed potent antitumor activity, especially the N-methyl piperazinyl substituted derivatives 6f and 6c, which displayed the most potent inhibitory activity with IC₅₀ values ranging from 8 to 17 nM. Docking the synthesized compounds into the epidermal growth factor receptor (EGFR), which is highly expressed in breast cancer, was employed to explore the possible interactions of these compounds with the EGFR. The activity of the reported compounds supports its clinical promise as a component of therapeutic strategies for cancer, for which high concentrations of chemotherapeutic agents are always a major limitation.

A series of benzothiazoles and benzoxazoles was synthesized and screened against two breast cancer cell lines, MCF-7 and MDA-231. Almost all compounds revealed potent antitumor activity, especially 6f and 6c against both cell lines.

A new series of 2-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole derivatives containing a 1,2,4-triazole ring were synthesized via microwave technique. This efficient procedure provides pure products within a few minutes. The newly synthesized compounds were confirmed by ¹H NMR and ¹³C NMR spectra and they were screened for their lipase inhibition and antioxidant activities. Compounds 4a, 4b, 5a, and 5b showed very good scavenging activity.

A series of 2-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole derivatives containing a 1,2,4-triazole ring were synthesized via microwave technique and screened for their lipase inhibition and antioxidant activities. Compounds 4a, 4b, 5a, and 5b showed very good scavenging activity.

Novel polyhydroxylated (E)-stilbenes were synthesized by Mizoroki–Heck reactions and tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them are good inhibitors of butyrylcholinesterase; one of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.

Novel polyhydroxylated (E)-stilbenes synthesized by Mizoroki–Heck reactions were tested for their ability to inhibit the enzymes acetyl- and butyrylcholinesterase. Several of them were found to be good inhibitors of butyrylcholinesterase. One of them carrying an extra fluorine substituent is a 94-fold stronger inhibitor of butyrylcholinesterase than of acetylcholinesterase.

Ureases have emerged as significant virulence factors implicated in the pathogenesis of many clinical conditions such as pyelonephritis, hepatic coma, peptic ulceration, and the formation of injection-induced urinary stones and stomach cancer. They have also been identified as important targets in research both for human and animal health, as well as in agriculture. Strategies based on urease inhibition are the main treatment of diseases caused by urease-producing bacteria. So, in the present context, a diverse library of chemical structures is known to possess remarkable inhibitory activities against urease enzymes. The current review article summarizes and discusses endeavours towards the developments in the burgeoning field of urease inhibition in medicinal chemistry, with an emphasis on the insights that have been gleaned into the structural features that contribute to high and promising levels of anti-urease activity.

Ureases have been implicated in the pathogenesis of many clinical conditions. Strategies based on urease inhibition are the main treatment of diseases caused by urease-producing bacteria. This review article surveys recent efforts undertaken for the identification, optimization and development of potent urease inhibitors.

Here, we provide an alternative synthesis of the natural bromophenol 3,4-dibromo-5-(2,3-dibromo-4,5-dihydroxybenzyl)-6-(ethoxymethyl)benzene-1,2-diol (3) and the first synthesis of (4,5-dihydroxy-2-methylphenyl)(3,4-dihydroxyphenyl)methanone (18) and its brominated derivatives 19–21. The compounds were characterized and tested against the two most studied members of the pH regulatory enzyme family, carbonic anhydrase (CA). The inhibitory potencies of the novel compounds and two natural bromophenols 2, 3 were analyzed at the human isoforms hCA I and hCA II as targets and the K_I values were calculated. The K_I values of the novel compounds were measured in the range of 13.7–32.7 µM for the hCA I isozyme and 0.65–1.26 µM for the hCA II isozyme. The structurally related compound 14 was also tested in order to understand the structure–activity relationship, and the clinically used sulfonamide acetazolamide (AZA) was tested for comparison reasons. All of the compounds exhibited competitive inhibition with 4-nitrophenylacetate as substrate. The compounds showed strong inhibitory activity against hCA I, being more effective as compared to the clinically used AZA (K_I: 36.2 µM), but rather less activity against hCA II.

An alternative synthesis of the natural bromophenol 3,4-dibromo-5-(2,3-dibromo-4,5-dihydroxybenzyl)-6-(ethoxymethyl)benzene-1,2-diol (3) and the first synthesis of (4,5-dihydroxy-2-methylphenyl)(3,4-dihydroxyphenyl)methanone (18) and its brominated derivatives 19–21 are provided. The compounds were tested against two human carbonic anhydrase isozymes, showing strong inhibitory activity against hCA I, but low activity against hCA II.

In this study, we synthesized some novel N-(tetrazol-1H-5-yl)-6,14-endoethenotetrahydrothebaine 7α-substituted 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives as potential analgesic agents. The structures of the compounds were established on the basis of their IR, ¹H NMR, ¹³C NMR, 2D NMR, and high-resolution mass spectral data. The analgesic activity was evaluated by a rat-hot plate test model and a rat tail-flick model. Compound 12 showed analgesic activity higher than that of morphine. In addition to a histopathological and biochemical evaluation, the LD₅₀ dose for the most active compound 12 was determined.

Novel N-(tetrazol-1H-5-yl)-6,14-endoethenotetrahydrothebaine 7α-substituted 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives were synthesized and their analgesic activity was evaluated by a rat hot-plate test model and a rat tail-flick model. Compound 12 showed analgesic activity higher than that of morphine.

1-(p-Methylphenyl)-3,5-diaryl-2-pyrazoline derivatives (2a–f) were synthesized via the treatment of 1-(1H-indol-3-yl)-3-aryl-2-propen-1-ones (1a–f) with p-methylphenylhydrazine hydrochloride in hot acetic acid. The structures of these compounds were elucidated by IR, ¹H NMR, and mass spectral data and elemental analysis. These compounds were investigated for their antimicrobial activity. Brine-Shrimp lethality assay was carried out to determine the toxicity of the compounds. Compound 2e, which is the pyrazoline derivative bearing the 2,5-dichlorophenyl moiety, can be identified as the most promising agent against Klebsiella pneumoniae (ATCC 13883) and Candida glabrata (ATCC 36583) due to its inhibitory effects on K. pneumoniae and C. glabrata with a MIC value of 100 µg/mL as a non-toxic agent (LC₅₀ > 1000 µg/mL).

1-(p-Methylphenyl)-3,5-diaryl-2-pyrazoline derivatives (2a–f) synthesized via the treatment of 1-(1H-indol-3-yl)-3-aryl-2-propen-1-ones with p-methylphenylhydrazine hydrochloride in hot acetic acid were investigated for their antimicrobial activity. Compound 2e bearing a 2,5-dichlorophenyl moiety was the most promising agent against Klebsiella pneumoniae and Candida glabrata.

A series of compounds derived from 4,5-dihydro-1H-1,2,4-triazol-5-one were synthesized and characterized by spectral data. The 12 new compounds were analyzed for their potential in vitro antioxidant activities by three different methods. Compound 4f showed the best activity for the iron binding. In addition, the compounds 4 were titrated potentiometrically with tetrabutylammonium hydroxide in non-aqueous solvents. The RP-HPLC capacity factors (k′) of the series were also determined on a C18 column, with methanol/water as the mobile phase. The correlation between log k′ with the percentage of methanol in the mobile phase was used for the determination of the log k_w values for these compounds. The antimicrobial activities of these compounds were also screened against bacteria and yeast.

1,2,4-Triazoles have a broad spectrum of biological activities. The synthesis and the in vitro antioxidant, antibacterial and antifungal evaluation of new 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives are described.

A novel series of 5-arylidene-2,4-thiazolidinediones (TZDs) 2a–p was synthesized from the condensation of 3-((2-phenylthiazol-4-yl)methyl)thiazolidine-2,4-dione with different benzaldehyde derivatives. All the structures were confirmed by their spectral (IR, ¹H NMR, ¹³C NMR and mass) and elemental analytical data. The new molecules were evaluated in vivo as anti-inflammatory agents in an acute experimental inflammation, evaluating the acute phase bone marrow response and phagocyte activity. All compounds, excepting one, reduced the absolute leukocytes count due to the lower neutrophil percentage. Phagocytary index was decreased by the same molecules, while only half of them reduced the phagocytary activity. The effect was superior to meloxicam, the reference anti-inflammatory drug, for the majority of the TZD derivatives. The new molecules were also investigated for their antimicrobial properties on Gram-positive and Gram-negative bacteria and one fungal strain. Two compounds (2e and 2n) manifested growth inhibition capacity on all the tested strains.

New 5-arylidene-2,4-thiazolidinediones (TZDs) 2a–p were synthesized and evaluated in vivo as anti-inflammatory agents. All except one displayed good results. The phagocytic parameters were decreased by the new molecules. The effect was superior to meloxicam, for the majority of the TZD derivatives. The compounds were also investigated for their antimicrobial properties. Two of them (2e and 2n) manifested growth inhibition capacity on all the tested strains.

Nine 4-arylphthalazones bearing benzenesulfonamide (2a–i) were synthesized by the condensation of the appropriate 2-aroylbenzoic acid (1a–i) and 4-hydrazinobenzenesulfonamide in ethanol. The structures of these compounds were elucidated by elemental analysis, IR, ¹H NMR, ¹³C NMR, and MS spectroscopy. Two compounds, 2b and 2i, showed significant anti-inflammatory activity comparable to that of the standard drug celecoxib in the carrageenan-induced rat paw edema model. These compounds (2b and 2i) had selective inhibitory activity towards the COX-2 enzyme. Compound 2b had a better selectivity ratio (COX-1/COX-2) compared to that of celecoxib and can be used as a novel template for the design of selective COX-2 inhibitors. Compounds 2d and 2i were screened for their antiproliferative activity toward 60 human cancer cell lines by the National Cancer Institute (USA). The compounds 2d and 2i displayed mild activity toward the renal cancer cell line UO-31.

Nine 4-arylphthalazones bearing benzenesulfonamide (2a–i) were synthesized by the condensation of the appropriate 2-aroylbenzoic acid (1a–i) and 4-hydrazinobenzenesulfonamide in ethanol. Compounds 2b and 2i showed anti-inflammatory activity comparable to that of celecoxib in the carrageenan-induced rat paw edema model. Compounds 2d and 2i were screened for their antiproliferative activity towards 60 human cancer cell lines, displaying mild activity toward the renal cancer cell line UO-31.