One‐Pot Laccase‐Catalysed Synthesis of 5,6‐Dihydroxylated Benzo[b]furans and Catechol Derivatives,and Their Anticancer Activity

A commercial laccase, Suberase® from Novozymes, was used to catalyse the synthesis of 5,6‐dihydroxylated benzo[b]furans and catechol derivatives. The yields were, in some cases, similar to or better than that obtained by other enzymatic, chemical or electrochemical syntheses. The synthesised derivatives were screened against renal (TK10), melanoma (UACC62), breast (MCF7) and cervical (HeLa) cancer cell lines. GI₅₀, TGI and LC₅₀ are reported for the first time. Anticancer screening showed that the cytostatic effects of the 5,6‐dihydroxylated benzo[b]furans were most effective against the melanoma (UACC62) cancer cell line with several compounds exhibiting potent growth inhibitory activities (GI₅₀ = 0.77–9.76 µM), of which two compounds had better activity than the anticancer agent etoposide (GI₅₀ = 0.89 µM). One compound exhibited potent activity (GI₅₀ = 9.73 µM) against the renal (TK10) cancer cell line and two exhibited potent activity (GI₅₀ = 8.79 and 9.30 µM) against the breast (MCF7) cancer cell line. These results encourage further studies of the 5,6‐dihydroxylated benzo[b]furans for their potential application in anticancer therapy.     

Exploration of imidazole and imidazopyridine dimers as anticancer agents: Design,synthesis, and structure–activity relationship study

Dimerization of proteins/receptors plays a critical role in various cellular processes, including cell proliferation and differentiation. Therefore, targeting such dimeric proteins/receptors by dimeric small molecules could be a potential therapeutic approach to treating various diseases, including inflammation‐associated diseases like cancer. A novel series of bis‐imidazoles ( 13–18 ) and bis‐imidazo[1,2‐a]pyridines ( 19–28 ) were designed and synthesized from Schiff base dimers ( 1–12 ) for their anticancer activities. All the synthesized compounds were screened for anticancer activities against three cancer cell lines, including cervical (HeLa), breast (MDA‐MB‐231), and renal cancer (ACHN). From structure–activity relationship studies, imidazo[1,2‐a]pyridines ( 19–28 ) showed remarkable cytotoxic activities, with compounds 19 and 24 showing the best inhibitory activities against all three cell lines. Especially, both 19 and 24 were very effective against the breast cancer cell line ( 19 , GI₅₀ = 0.43 µM; 24 , GI₅₀ = 0.3 µM), exceeding the activity of the control adriamycin (GI₅₀ = 0.51 µM). The in vivo anticancer activity results of compounds 19 and 24 were comparable with those of the animals treated with the standard drug tamoxifen. Therefore, the dimeric imidazo[1,2‐a]pyridine scaffold could serve as a potential lead for the development of novel anticancer agents.     

Design,synthesis, molecular docking,and anticancer evaluations of 1-benzylquinazoline-2,4(1H,3H)-dione bearing different moieties as VEGFR-2 inhibitors

A novel series of 1-benzylquinazoline-2,4(1H,3H)-dione derivatives, 6a , b to 11a – e , was designed, synthesized, and evaluated for their anticancer activity against HepG2, HCT-116, and MCF-7 cells. Compounds 11b , 11e , and 11c were found to be the most potent derivatives of all tested compounds against the HepG2, HCT-116, and MCF-7 cancer cell lines, with GI₅₀ = 9.16 ± 0.8, 5.69 ± 0.4, 5.27 ± 0.2 µM, 9.32 ± 0.9, 6.37 ± 0.7, 5.67 ± 0.5 µM, and 9.39 ± 0.5, 6.87 ± 0.7, 5.80 ± 0.4 µM, respectively. These compounds exhibited nearly the same activity as sorafenib against HepG2 and HCT-116 cells and a higher activity against MCF-7 cells (GI₅₀ = 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively). Also, these compounds displayed a lower activity than doxorubicin against HepG2 cells and a higher activity against HCT-116 and MCF-7 cells (GI₅₀ = 7.94 ± 0.6, 8.07 ± 0.8, and 6.75 ± 0.4 µM, respectively). The most active antiproliferative derivatives, 6a , b , 8 , 9 , and 11a – e , were selected to evaluate their enzymatic inhibitory activity against VEGFR-2. Compounds 11b , 11e , and 11c potently inhibited VEGFR-2 at IC₅₀ values of 0.12 ± 0.02, 0.12 ± 0.02, and 0.13 ± 0.02 µM, respectively, which are nearly equipotent as sorafenib IC₅₀ value (0.10 ± 0.02 µM). Furthermore, molecular docking studies were performed for all synthesized compounds to assess their binding pattern and affinity toward the VEGFR-2 active site.     

Design and synthesis of new 2,5-disubstituted-1,3,4-oxadiazole analogues as anticancer agents

In continuance of our search for new anticancer agents, we report herein the design, synthesis, and anticancer evaluation of oxadiazole analogues. Two series (4a-h and 4i-q) of new oxadiazole analogues were designed based on heterocyclic (1,3,4-oxadiazole)-linked aryl core of IMC-038525 (tubulin polymerization inhibitor), NSC 776715, and NSC 776715 and synthesized. All the compounds were fully characterized by infrared, nuclear magnetic resonance spectroscopy, and mass spectral data and the purity of compounds was checked by elemental analysis (C, H, and N analysis). Further seven compounds were evaluated for anticancer activity on nine different panels of 60 cell lines (60 NCI cancer cell lines) according to the National Cancer Institute screening protocol and percent growth and percent growth inhibition was calculated at 10?µM drug concentration. Ten compounds were evaluated for anticancer activity on two cancer cell lines (HeLa and MDA-MB-435) as per the standard protocol reported at four different drug concentrations (10^?7, 10^?6, 10^?5, and 10^?4?µM) and GI₅₀, LC₅₀, and TGI dose-related parameters were calculated. The compound 4j showed maximum anticancer activity at 10?µM, and was found to have higher sensitivity against MOLT-4, IGROV1, HCT-116, and K-562 with percent growth inhibitions of 50.38, 48.45, 46.26, and 46.26 respectively. The compound 4j showed superior anticancer activity than imatinib on 41 human cancer cell lines. The compound 4p showed anticancer activity with GI₅₀ of 36.7 and 46.5?µM against HeLa and MDA-MB-435 cell lines, respectively.     

Synthesis and Biological Evaluation of Novel Pyrazoles and Pyrazolo[3,4‐d]pyrimidines Incorporating a Benzenesulfonamide Moiety

Synthesis and biological evaluation of novel pyrazoles and pyrazolo[3,4‐d]pyrimidines are reported. Fourteen compounds were selected by the NCI and tested for their preliminary in‐vitro anticancer activity, whereas all the synthesized compounds were evaluated for their in‐vitro antimicrobial activity. Compound 12a was proven to possess the highest anticancer activity with a broad spectrum profile. It showed particular effectiveness towards leukemia HL‐60 (TB), K‐562, non‐small cell lung cancer NCI‐H23, and colon cancer HT 29, KM 12 cell lines (GI₅₀ = 6.59, 4.44, 1.37, 3.33, and 9.63 μM, respectively). Out of the synthesized compounds, thirteen derivatives were found to display pronounced antimicrobial activity especially against P. aeruginosa. Compounds 2c , 5b , 10 , 11b , 17b , 18b , and 19 were proven to be the most active with a broad spectrum of activity. Compound 19 was found to be equipotent to ampicillin against B. subtilis, whereas compounds 11b and 19 were four times superior to ampicillin against P. aeruginosa, while compounds 5b and 18b were equipotent to ampicillin against the same organism. Moreover, compounds 2c , 10 , and 11b were nearly equipotent to ampicillin against E. coli. On the other hand, compounds 2c , 5b , 10 , 11a , 17b , and 18b exerted nearly half the activity of clotrimazole against C. albicans.     

A facile synthesis of some 3-cyano-1,4,6-trisubstituted-2(1H)-pyridinones and their biological evaluation as anticancer agents

The synthesis of some new 3-cyano-1,4,6-trisubstituted-2(1H)-pyridinones supported with various pharmacophores and functionalities at positin-1 is described. The in vitro anticancer activity of 24 of the newly synthesized compounds was evaluated according to the protocol of the NCI in vitro disease-oriented human cells screening panel assay. The results revealed that five compounds 4a–c, 7b, and 12b were able to display moderate antitumor potential against some of the tested subpanel tumor cell lines at the GI₅₀ and TGI levels, however, with marginal or no cytotoxic (LC₅₀) activity. The obtained data suggested that better antitumor activity was linked to derivatives with either 4-bromophenyl or 3,4-dimethoxyphenyl moieties, together with a 1-methyl-1H-pyrrol-2-yl counter part at positions 6 and 4, respectively. Consequently, the 3-cyano-4-(1-methyl-1H-pyrrol-2-yl)-6-(4-bromophenyl or 3,4-dimethoxyphenyl)-2(1H)-pyridinones 4a and 4b, could be considered as the most active members identified in this investigation as evidenced from their relative higher growth inhibitory (GI₅₀ (MG-MID) 77.6 and 67.6 μM, respectively) and cytostatic (TGI (MG-MID) 85.1 and 95.5 μM, respectively) activities, when compared with the substituted thiocarbamoyl analog 7b and the bicyclic [1,2,4]triazolo[3,4-a]pyridine derivative 12b.     

Synthesis and Biological Evaluation of 1,2,3‐triazole tethered Pyrazoline and Chalcone Derivatives

A series of pyrazoline derivatives and corresponding chalcone intermediates with substituents same as combretastatin‐A4(CA‐4) conjugated with triazole nucleus has been synthesized and evaluated for their anticancer potential. Sulphorhodamine B(SRB) assay indicated compound 12c to be the most active compound from the series with GI₅₀ value of 6.7 μm against the human liver carcinoma cell line HepG2. Interestingly, the intermediate 11c exhibited more promising cytotoxicity demonstrating GI₅₀ value of 1.3 μm against the prostate cancer cell line DU145. Compounds 11c and 12c caused accumulation of cells in G2/M phase and inhibited tubulin polymerization. Furthermore, these compounds reduce the mitochondrial membrane potential and activate caspases 3 and 9, thereby indicating their ability to trigger apoptosis.     

Design,synthesis, and antitumor evaluation of quinoline‐imidazole derivatives

A series of compounds bearing quinoline‐imidazole ( 8a–e , 9a–e , 10a–e , 11a–e , and 12a–e ) not reported previously were designed and synthesized. The target compounds were evaluated for antitumor activity against A549, PC‐3, HepG2, and MCF‐7 cells by the MTT method, with NVP‐BEZ235 being the positive control. Most compounds showed moderate activity and compound 12a showed the best activity against HepG2, A549, and PC‐3 cells, with half‐maximal inhibitory concentration (IC₅₀) values of 2.42 ± 1.02 µM, 6.29 ± 0.99 µM, and 5.11 ± 1.00 µM, respectively, which was equal to NVP‐BEZ235 (0.54 ± 0.13 µM, 0.36 ± 0.06 µM, 0.20 ± 0.01 µM). Besides, the IC₅₀ value of 12a against the cell line WI‐38 (human fetal lung fibroblasts) was 32.8 ± 1.23 µM, indicating that the target compounds were selective for cancer cells. So, 11a and 12a were evaluated against PI3Kα and mTOR to find out if the compounds acted through the PI3K‐Akt‐mTOR signal transduction pathway. The inhibition ratios to PI3Kα and mTOR were slightly lower than that of NVP‐BEZ235, suggesting there may be some other mechanisms of action. The structure–activity relationships and docking study of 11a and 12a revealed that the latter was superior. Moreover, the target compounds showed better in vitro anticancer activity when the C‐6 of the quinoline ring was replaced by a bromine atom.

     

Design,synthesis, and docking study of new quinoline derivatives as antitumor agents

New quinolines substituted with various heterocycles and chalcone moieties were synthesized and evaluated as antitumor agents. All the synthesized compounds were in vitro screened against 60 human cancer cell lines. Compound 13 showed the highest cytotoxicity toward 58 cell lines, exhibiting distinct growth inhibition values (GI₅₀) against the majority of them, including SR, HL‐60 (TB) strains (leukemia), and MDA‐MB‐435 strains (melanoma), with GI₅₀ values of 0.232, 0.260, and 0.300 µM, respectively. It exhibited great selectivity toward cancer cell lines, with less toxic effect against normal cells represented by skin fibroblast (BJ) and breast epithelial cell lines (MCF‐10F). The enzyme inhibitory activity of compound 13 was evaluated against topoisomerase 1 (Topo 1), epidermal growth factor receptor and vascular endothelial growth factor receptor 2, where it displayed worthy Topo 1 inhibition activity with an IC₅₀ value of 0.278 µM compared with camptothecin as a reference drug (IC₅₀ 0.224 µM). Docking studies were performed to investigate the recognition profile of compound 13 with the Topo 1 enzyme binding site.     

Benzoxazole/benzothiazole‐derived VEGFR‐2 inhibitors: Design,synthesis, molecular docking,and anticancer evaluations

A novel series of benzoxazole/benzothiazole derivatives 4a–c – 11a–e were designed, synthesized, and evaluated for anticancer activity against HepG2, HCT‐116, and MCF‐7 cells. HCT‐116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 4c was found to be the most potent derivative against HepG2, HCT‐116, and MCF‐7 cells, with IC₅₀ values = 9.45 ± 0.8, 5.76 ± 0.4, and 7.36 ± 0.5 µM, respectively. Compounds 4b, 9f , and 9c showed the highest anticancer activities against HepG2 cells with IC₅₀ values of 9.97 ± 0.8, 9.99 ± 0.8, and 11.02 ± 1.0 µM, respectively, HCT‐116 cells with IC₅₀ values of 6.99 ± 0.5, 7.44 ± 0.4, and 8.15 ± 0.8 µM, respectively, and MCF‐7 cells with IC₅₀ values of 7.89 ± 0.7, 8.24 ± 0.7, and 9.32 ± 0.7 µM, respectively, in comparison with sorafenib as reference drug with IC₅₀ values of 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively. The most active compounds 4a–c, 9b,c,e,f,h , and 11c,e were further evaluated for their VEGFR‐2 inhibition. Compounds 4c and 4b potently inhibited VEGFR‐2 at IC₅₀ values of 0.12 ± 0.01 and 0.13 ± 0.02 µM, respectively, which are nearly equipotent to the sorafenib IC₅₀ value (0.10 ± 0.02 µM). Furthermore, molecular docking studies were performed for all synthesized compounds to assess their binding pattern and affinity toward the VEGFR‐2 active site.     

Investigation of the antimicrobial and anticancer activity of aminonaphthoquinones

In this study, we report on the inhibitory activity of synthesized aminonaphthoquinones against two bacterial and one fungal species to determine their antimicrobial properties. A minimum inhibitory concentration (MIC) of 7.8 μg/mL was obtained against the fungus, Candida albicans, which was better than that of Amphotericin B (MIC = 31.25 μg/mL). Escherichia coli (Gram -), was inhibited at a MIC of 23.4 μg/mL and Staphylococcus aureus (Gram +) at a MIC of 31.3 μg/mL. The aminonaphthoquinones were also screened against HCT116 colon, PC3 prostate and HepG2 liver cancer cell lines to evaluate their cytostatic effects. They had potent activity (GI₅₀ = 5.87–9.90 μM) which was about three-6-fold better than that of parthenolide (GI₅₀ = 25.97 μM) against the prostate cancer cell line. These compounds were generally more selective for cancer cells than for normal human lung fetal fibroblasts (WI-38).     

Synthesis and Biological Evaluation of Mercapto Triazolo‐Benzothiadiazine Linked Aminobenzothiazoles as Potential Anticancer Agents

The synthesis of a series of 10‐substituted 5,5‐dioxo‐5,10‐dihydro[1,2,4]triazolo[4,3‐b][1,2,4]benzothiadiazine coupled with sulfanylacetamido benzothiazole pharmacophores ( 5a – g ) is described. All the synthesized compounds have been evaluated for their anticancer activity. Most of the compounds showed significant growth inhibitory activity against selected human tumor cell lines. Interestinlgy, one of the synthesized compounds 5d, exhibited GI₅₀ values of 1.4 and 2.1 μm against RPMI‐8226 (leukemia) and HOP‐62 (lungs) cell lines, respectively.     

Novel pyrazolopyrimidine urea derivatives: Synthesis,antiproliferative activity,VEGFR-2 inhibition,and effects on the cell cycle profile

A series of novel diaryl urea pyrazolopyrimidine derivatives was designed and synthesized. All the synthesized compounds were evaluated for cytotoxic activity by the National Cancer Institute. A significant antiproliferative activity at a 10-µM dose was shown by four compounds ( 5c, 5e, 5g , and 5h ), and they were accordingly evaluated at five concentrations. They showed a potent and broad-spectrum antiproliferative activity, with GI₅₀ values between 0.553 and 3.80 µM and TGI values in the range of 2.17–100 µM. These four compounds potently inhibited the vascular endothelial growth factor receptor-2 (VEGFR-2) with IC₅₀ values in the nanomolar range. Molecular docking attributed their potent VEGFR-2 inhibitory activity to their interactions with key amino acids in the VEGFR-2 active site. Their flow cytometric analysis showed that they exerted their cytotoxic activity by reduction of the cellular proliferation and by induction of cell cycle arrest at the G2/M phase. Additionally, they induced DNA degradation or fragmentation, confirming the role of apoptosis in the cancer cell death and cytotoxicity induced by these compounds.     

Design and synthesis of new 2‐anilinoquinolines bearing N‐methylpicolinamide moiety as potential antiproliferative agents

A series of new 2‐anilinoquinolines 6a – o possessing the substantial N‐methylpicolinamide motif at C5 has been designed and synthesized as sorafenib analogs. The antiproliferative activities of the target compounds were preliminarily appraised against a panel of three human cancer cell lines (MCF‐7, SK‐BR3, and HCT116), and a selected array was further tested over a panel of approximately 60 cancer cell lines at NCI at 10 μM concentration. Interestingly, compounds 6c , 6d , 6j , 6k , and 6l showed promising selective anticancer activities (growth inhibition >80%) toward certain cancer cells at 10 μM testing dose. Compounds 6d and 6j were advanced to five‐dose testing mode to determine their GI₅₀ values and compared with our previously reported ureidoquinoline B and sorafenib as reference compounds. The 4‐chloro‐3‐trifluoromethylaniline derivative 6j manifested superior potency than both compound B and sorafenib over eleven and eight cell lines, respectively. It showed GI₅₀ values of 0.36, 0.66, 0.68, and 0.60 μM against the breast MDA‐MB‐468, renal A498, and melanoma SK‐MEL‐5 and UACC‐62 cell lines, respectively. Moreover, both 6d and 6j exerted low cytotoxic effects against HFF‐1 normal cell line. Furthermore, compounds 6d and 6j were tested against both B‐Raf^V600E and C‐Raf kinases and displayed modest inhibitory activities, which were justified by molecular docking study. Compound 6j could serve as a promising candidate for further development of potent anticancer chemotherapeutics.     

Synthesis of some sulfonamides,disubstituted sulfonylureas or thioureas and some structurally related variants. A class of promising antitumor agents

Some new benzenesulfonamides, disubstituted sulfonylureas, and sulfonylthioureas substituted basically with 3-(2-thienyl or 3-pyridyl)-indeno[1,2-c]pyrazol(in)e counterpart were synthesized to be evaluated for their in vitro antitumor activity. Some of the thioureido derivatives were cyclized to the corresponding five-membered thiazolidinons, thiazolines, and the six-membered thiazinones as interesting structure variants. According to the protocol of the National Cancer Institute (NCI) in vitro disease-oriented human cells screening panel assay, 13 compounds showed promising broad spectrum antitumor activity. In general, compounds containing the thienyl moiety displayed better antitumor spectra than those containing the pyridyl moiety. Compound 5, 4-(3-(2-thienyl)-3H-indeno[1,2-c]pyrazol-2-yl)-benzenesulfonamide [GI₅₀, TGI, and LC₅₀ (MG-MID) values of 13.2, 33.1 and 69.2 μM, respectively] proved to be the most active member in this study with variable degrees of potencies against all the tested subpanel tumor cell lines and particular effectiveness against the leukemia and prostate subpanels at both the GI₅₀ (3.30 and 8.68 μM, respectively) and the TGI levels (15.7 and 22.3 μM, respectively).     

Cell Cycle Arrest and Apoptosis Induction by an Anticancer Chalcone Epoxide

Safe and effective chemotherapeutic agents for the treatment of pancreatic cancer remain elusive. We found that chalcone epoxides (1,3‐diaryl‐2,3‐epoxypropanones) inhibited growth in two pancreatic cancer cell lines, BxPC‐3 and MIA PaCa‐2. Three compounds were active, with GI₅₀ values of 5.6 to 15.8 µM. Compound 4a , 1,3‐bis‐(3,4,5‐trimethoxyphenyl)‐2,3‐epoxypropanone, had an average GI₅₀ of 14.1 µM in the NCI 60‐cell‐line panel. To investigate the mode of action, cell cycle analyses of BxPC‐3 cells were carried out. Treatment of cells with 50 µM 4a resulted in dramatic accumulation at G2/M (61% after 12 h for 4a vs. 15% for untreated cells). The cells rapidly entered apoptosis. After 12 h, 26% of cells treated with 50 µM 4a had entered apoptosis vs. 4% for cells treated with 100 µM etoposide and 2% for untreated cells. Compound 4a interfered with paclitaxel enhancement of tubulin polymerization, suggesting microtubules as the site of action. Reaction of thiol nucleophiles with 4a under basic conditions resulted in epoxide ring‐opening and retroaldol fragmentation, yielding alkylated thiol. MALDI mass spectrometry showed that retroaldol reaction occurred upon treatment of β‐tubulin with 4a . The site of alkylation was identified as Cys³⁵⁴. Chalcone epoxides warrant further study as potential agents for treatment of cancer.     

Novel Pyrazole and Indazole Derivatives: Synthesis and Evaluation of Their Anti‐Proliferative and Anti‐Angiogenic Activities

The synthesis of several new pyrazole and indazole derivatives from acetophenone and tetralone substrates is reported. The bioactivities of the new compounds were evaluated through in vitro assays for endothelial cell proliferation and tube formation. Results herein indicate that the easily prepared compounds containing the indazole structural framework exhibit potent cytostatic properties against all cell lines tested, with compounds 13 and 14 being the most active displaying IC₅₀ values of 1.5 ± 0.4 µM and 5.6 ± 2.5 µM, respectively, against MCF‐7 cells. In addition, the indazole derivative 16 was assessed as a competent inhibitor of endothelial tube formation at 30 µM.     

New quinazolinone-based derivatives as DHFR/EGFR-TK inhibitors: Synthesis,molecular modeling simulations,and anticancer activity

New 2-mercapto-quinazolin-4-one analogs were synthesized and tested for their in vitro anticancer activity, dihydrofolate reductase (DHFR) inhibition, and epidermal growth factor tyrosine kinase (EGFR-TK) inhibition activities. Compound 24 , which is characterized by a 2-benzyl-thio function, showed broad-spectrum anticancer activity with high safety profile and selectivity index. The concentrations of 24 causing 50% growth inhibition (GI₅₀) and total cell growth inhibition (TGI) and its lethal concentration 50 (LC₅₀) were 15.1, 52.5, and 91.2 µM, respectively, using 5-fluorouracil as a positive control. Also, it showed EGFR-TK inhibitory activity with IC₅₀ = 13.40 nM compared to gefitinib (IC₅₀ = 18.14 nM) and DHFR inhibitory potency with 0.30 μM compared to methotrexate (MTX; IC₅₀ = 0.08 μM). In addition, compound 24 caused cell cycle arrest and apoptosis on COLO-205 colon cancer cells. Compounds 37, 21 , and 54 showed remarkable DHFR inhibitory activity with IC₅₀ values of 0.03, 0.08, and 0.08 μM, respectively. The inhibitory properties of these compounds are due to an electron-withdrawing group on the quinazolinone ring, except for compound 54 . In a molecular modeling study, compound 24 showed the same binding mode as gefitinib as it interacted with the amino acid Lys745 via π–π interaction. Compound 37 showed a similar binding mode as MTX through the binding interaction with Lys68, Asn64 via hydrogen bond acceptor, and Phe31 via arene–arene interaction. The obtained model and substitution pattern could be used for further development.     

3-Cyano-4,6-disubstituted-2(1H)-imino or oxopyridines: New Antineoplastic Agents with High Selectivity Towards Leukemia Cell Lines

Two series of 3-cyano-2(1H)-oxopyridine and 3-cyano-2(1H)-iminopyridine derivatives carrying various aryl substituents at position 4 and (4-((7-chloro or trifluoromethylquinol-4-yl)amino)phenyl) substituent at position 6 were synthesized and evaluated for their antitumor activity. Compounds 3f and 6d showed high selectivity towards leukemia cell lines with full panel median growth inhibition GI₅₀ average sensitivity towards all cell lines (MG-MID) at 7.9 and 19.7 μM and leukemia subpanel GI₅₀ average sensitivity towards leukemia cell lines (MG-MID) at 1.74 and 2.9 μM, respectively, also they exhibited full panel total growth inhibition TGI (MG-MID) at 34.8 and 59.0 μM and leukemia subpanel TGI (MG-MID) at 5.3 and 13.5 μM, respectively.     

Synthesis and Biological Evaluation of Novel Bromophenol Derivatives as Carbonic Anhydrase 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.