Quinazolinone derivatives as new potential CDK4/6 inhibitors, apoptosis inducers and radiosensitizers for breast cancer

Background: Targeting CDK4/6 has advanced breast cancer treatment. Herein, new quinazolinones were synthesized with acetamide linkers as potential anti-breast cancer agents. Methods & results: In vitro cytotoxic evaluation on human breast cancer cell lines (MCF7 and MDA-MB-231) identified 1,3-benzodioxole (5d) to be of the highest potency. It showed good inhibitory activity on CDK4/6. Compound 5d arrested the cell cycle at the G1-phase, caused induction of early and late apoptosis in an Annexin V-FITC assay, led to an increase in the level of caspase-3 and upregulated Bax expression and downregulated Bcl-2 in MCF7 cells. Compound 5d showed good radiosensitizing activity when combined with a single dose of 8-Gy γ-radiation. Conclusion: This study introduces quinazolinone scaffolds as new CDK4/6 inhibitors for breast cancer.

Pyrazole-sulfonamide scaffold featuring dual-tail strategy as apoptosis inducers in colon cancer

Dual-tail strategy has been successfully utilized in the development of novel carbonic anhydrase IX (CA IX) inhibitors. Herein we adopted this approach in the design and synthesis of a series of novel pyridine sulfonamide-pyrazole hybrid scaffold mimicking dual-tail inhibitors of CA IX. A library of 15 compounds was synthesized and assessed for their potential cytotoxic effects against colorectal cancer cells. Compounds 3, and 11 induced potential cytotoxic effects against the three cancer cell lines (HCT-116, HT-29, and SW-620) with IC₅₀s' of 45.88, 28.27, and 16.57 uM, 25.01, 8.99, and 3.27 µM, respectively. Both compounds induced cellular apoptosis on HCT-116 and SW-620 cells, while compound 3 induced necrosis as well. In addition, both compounds induced cell cycle arrest on G0/G1, and S phases. Also, compound 11 showed potential autophagy induction on both colon cancer cell lines (HCT-116, and HT-29), and a little bit on metastatic type. Both compounds were less cytotoxic than the reference drug on normal epithelial cell. The migration rates of HCT-116 and the metastatic one SW-620 were reduced by both compounds. Finally, molecular docking of compounds 3 and 11 into the active site of CA IX confirmed in vitro inhibitory activity for both compounds.

Computational, in vitro and radiation-based in vivo studies on acetamide quinazolinone derivatives as new proposed purine nucleoside phosphorylase inhibitors for breast cancer

The present work describes a quinazolinone-based lead optimization for the development of novel purine nucleoside phosphorylase (PNP) inhibitors with quinazolinone scaffold. Nineteen compounds were proposed and docked against PNP, the best 14 compounds with highest docking and affinity scores and low RMSD values were synthesized. Synthesis of new quinazolinone derivatives with variable acetamide substituents on two positions on quinazoline ring was performed. The structures assigned to the products were concordant with the microanalytical and spectral data. In vitro cytotoxicity on human breast cancer cell line (MCF7) was performed and identified compound 6g as the most potent with IC₅₀ (0.99 ± 0.11 μM) which was further tested against five different breast cancer cell lines in addition to normal breast cell to determine the selectivity. Compound 6g was subjected to molecular dynamic simulation study, radiolabelling and biodistribution study to investigate its stability and selectivity toward breast cancers. The in vitro PNP inhibition results were aligned with the in silico, cytotoxicity, and biodistribution results where 6g showed the most potent PNP inhibitory activity with IC₅₀ (0.159 ± 0.007 μM) when compared to Peldesine (BCX-34) IC₅₀ (0.041 ± 0.002 μM).

Green synthesis of novel antifungal 1,2,4-triazoles effective against γ-irradiated Candida parapsilosis

This study reports the green synthesis of 11 novel 3-substituted-4-amino-5-mercapto-1,2,4-triazole derivatives using water as a readily available nontoxic solvent. Evaluation of their antimicrobial potential against several clinical pathogenic microorganisms was carried out. The newly synthesized cysteine derivative 6 showed promising antifungal activity against both γ-irradiated and nonirradiated Candida parapsilosis 216, with the lowest MIC (minimum inhibitory concentration) value of 3.125 µg/ml, probably through inhibition of 14α-demethylase. In addition, compound 6 showed complete inhibition of gelatinase, a virulence enzyme of C. parapsilosis. Also, scanning electron microscopy was carried out. Interestingly, compound 6 acted as a dual agent as it also showed good antibacterial activity against strains of Gram-positive bacteria used in the study. The synthesized compounds showed no cytotoxicity.

Anti-inflammatory and analgesic effect of LD-RT and some novel thiadiazole derivatives through COX-2 inhibition

Generally, highly selective COX-2 inhibitors cause cardiovascular side effects. Celecoxib is the highly marketed coxib, so there is still a need for the synthesis of COX-2 inhibitors with less adverse effects. Moreover, low-dose radiotherapy (LD-RT) is clinically used for the treatment of inflammatory diseases. The present study aimed to investigate the analgesic and anti-inflammatory activity of a novel series of 1,3,4-thiadiazole derivatives alone or combined with LD-RT with a single dose of 0.5 Gy. Initially, in vitro COX-1/COX-2 inhibition assays were performed, identifying the sulfonamide-containing compounds 5-10 as the most potent candidates, with IC₅₀ values in the range of 0.32-0.37 µM and the highest selectivity indices. These compounds and celecoxib were subjected to in vivo examination after their safety was assessed through the acute toxicity test. Treatment with compounds 5-10 inhibited carrageenan-induced edema by nearly 47-56%, which was nearly equivalent to celecoxib. Compounds 7 and 8 and celecoxib showed an analgesic activity of 64.15%, 49.05%, and 84.90%, respectively, whereas compounds 5, 6, 9, and 10 did not show any analgesic activity unless combined with LD-RT. Ulcerogenic activity, histological paw examination, and docking studies were performed. Compounds 5-10 were nearly similar to celecoxib, showing normal histological features with no ulcerogenic activity.

Novel Anticancer Fused Pyrazole Derivatives as EGFR and VEGFR-2 Dual TK Inhibitors

EGFR and VEGFR-2 represent promising targets for cancer treatment as they are very important in tumor development as well as in angiogenesis and metastasis. In this work, 6-amino-4-(2-bromophenyl)-3-methyl-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile 1 and (E)-4-(2-Bromobenzylidene)-5-methyl-2,4-dihydro-3H-pyrazol-3-one 11 were selected as starting materials to synthesize different fused pyrazole derivatives; dihydropyrano[2,3-c]pyrazole 1, 2, 7–9, and 15, pyrazolo[4′,3′:5,6]pyrano[2,3-d]pyrimidine 3–6, pyrazolo[3,4-d]pyrimidine 12 and 13, and pyrazolo[3,4-c]pyrazole 14 derivatives were synthesized to evaluate their anticancer activity against HEPG2 human cancer cell lines compared to erlotinib and sorafenib as reference drugs. Seven compounds 1, 2, 4, 8, 11, 12, and 15 showed nearly 10 fold higher activity than erlotinib (10.6 μM) with IC₅₀ ranging from 0.31 to 0.71 μM. In vitro EGFR and VEGFR-2 inhibitory activity were performed for the synthesized compounds, and the results identified compound 3 as the most potent EGFR inhibitor (IC₅₀ = 0.06 μM) and compound 9 as the most potent VEGFR-2 inhibitor (IC₅₀ = 0.22 μM). Moreover, compounds 9 and 12 revealed potent dual EGFR and VEGFR-2 inhibition, and these results were supported by docking studies of these two compounds within the active sites of both enzymes.

Synthesis and antimicrobial evaluation of new halogenated 1,3-Thiazolidin-4-ones

The ongoing prevalence of multidrug-resistant bacterial pathogens requires the development of new effective antibacterial agents. In this study, two series of halogenated 1,3-thiazolidin-4-ones were synthesized and characterized. All the synthesized thiazolidinone derivatives were evaluated for their antimicrobial activity. Biological screening of the tested compounds revealed the antibacterial activity of the chlorinated thiazolidinones 4a, 4b and 4c against Escherichia coli TolC-mutant, with MIC values of 16 µg/mL. A combination of a sub-inhibitory concentration of colistin (0.25 × MIC) with compounds 4a, 4b or 4c showed antibacterial activity against different Gram-negative bacteria (MICs = 4-16 µg/mL). Interestingly, compounds 4a, 4b and 4c were not cytotoxic to murine fibroblasts and Caco-2 cells. The chlorinated thiazolidinone derivative 16d demonstrated a bacteriostatic activity against a panel of pathogenic Gram-positive bacteria, including clinical isolates of methicillin and vancomycin-resistant Staphylococcus aureus, Listeria monocytogenes and multidrug-resistant Staphylococcus epidermidis (MICs = 8 - 64 µg/mL), with no cytotoxicity against both Caco-2 and L929 cells. Compound 16d was superior to vancomycin in disruption of the pre-formed MRSA biofilm. Furthermore, the three fluorinated thiazolidinone derivatives 26c, 30c and 33c showed a hindrance to hemolysin activity, without cytotoxicity against L929 cells.

Design and synthesis of novel pyridazinoquinazoline derivatives as potent VEGFR-2 inhibitors: In vitro and in vivo study

Worldwide, Hepatocellular Carcinoma (HCC) endures to be a prominent cause of cancer death. Treatment of HCC follows multiple therapies which are not entirely applicable for treatment of all patients. HCC usually arises contextual to chronic liver diseases and is often discovered at later stages which makes treatment options more complex. The present study aimed at design, synthesis & evaluation of new pyridazinoquinazoline derivatives as potential nontoxic anti-hepatocellular carcinoma (HCC) agents, through inhibition of Vascular endothelial growth factor -2 (VEGFR-2). Novel Pyridazino[3, 4, 5-de]quinazoline derivatives (2-6) were designed & synthesized. Their structures were confirmed via spectral and microanalytical data. They were tested for their in vitro VEGFR-2 inhibition & anticancer activity against human liver cancer cell line (HEPG-2). Molecular docking was investigated into VEGFR-2 site. In vivo studies of VEGRF-2 inhibition and the anti-apoptotic effect of the new compounds were determined in liver of irradiated rats. Toxicity of synthesized compounds was also assessed. The results showed that compounds 3-6 have significant antitumor activity and proved to be non-toxic. The ethoxy aniline derivative 6, exhibited the highest activity both in vitro and in vivo compared to the reference drug used, sorafenib. Compound 6 could be considered a promising nontoxic anti HCC agent and this could be partially attributed to its VEGFR-2 inhibition. Future preclinical investigation would be carried out to confirm the specific and exact mechanism of action of these derivatives especially compound 6 as an effective pharmaceutical agent after full toxicological and pharmacological assessment.

Carbonic anhydrase inhibition with a series of novel benzenesulfonamide-triazole conjugates

We report the synthesis and characterisation of a novel series of triazole benzenesulfonamide derivatives, which incorporate the general pharmacophore associated with carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The synthesised compounds were tested in vitro against four human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes, hCA I, hCA II, hCA IV and hCA IX. The obtained results showed that the tumour-associated hCA IX was the most sensitive to inhibition with the synthesised derivatives, with the triazolo-pyridine benzenesulfonamides 14, 16 and 17 being the most effective inhibitors. Some selected compounds were chosen for a single dose anti-proliferative activity testing against a panel of 57 human tumour cell lines and show some anti-proliferative activity ex vivo.

Novel thioureido-benzenesulfonamide derivatives with enaminone linker as potent anticancer, radiosensitizers and VEGFR2 inhibitors

In this study, novel series of thioureido-benzenesulfonamide derivatives bearing an enaminone linker either meta or para oriented and having terminal linear or substituted aromatic or heteroaromatic ring system 5-16a,b were designed and synthesized based on the general pharmacophoric features of type II VEGFR2 inhibitors. Evaluation of the synthesized compounds against HEPG2 hepatocellular carcinoma cells in vitro identified compounds 5b, 6b and 10-13b as most active anticancer agents with IC50 equal to 0.12, 0.29, 0.58, 0.44, 0.42 and 0.66 µM, respectively. These compounds were evaluated for their ability to in vitro inhibit VEGFR2 kinase enzyme. The results demonstrated highly potent dose-related VEGFR2 inhibition with IC50 values in nanomolar range (33, 57, 210, 37, 37 and 220 nM, respectively). The radiosensitizing ability of the most promising compounds was studied which showed an increase in the cell killing effect of radiation after combination with the synthesized compounds which revealed lowered IC50 by nearly 50%. Molecular docking for the most potent compounds was performed to predict their possible binding mode within VEGFR2 active site and they showed binding affinity in a similar way to sorafenib.

Anticancer Evaluation and Docking Study of New Bifunctional Phthalazine Derivatives

Materials and Methods:

The newly synthesized compounds were characterized by spectroscopic measurements and were tested for their in vitro anticancer activity by MTT assay against human liver cancer cell line. Docking study of all the synthesized compounds was performed within the active site of the enzyme VEGFR-2 (Vascular Endothelial Growth Factor Receptor-2).

Results:

The quinazoline derivative 12 emerged as the most potent compound in this study with an IC50 value of 5.4 µM. Docking study showed that the synthesized compounds were fit in the VEGFR-2 active site almost at the same position of sorafenib and vatalanib with comparable docking scores (-15.20 to -8.92 was kcal/mol).

Conclusion:

we have synthesized a novel series of phthalazine derivatives and evaluated their potential anticancer activity against HEPG2 cell line. The quinazoline derivative 12 emerged as the most potent compound in this study with an IC50 value of 5.4 µM. The SAR and docking studies pointed out that rigidification of the structure resulted in better activity and better binding within the active site of VEGFR-2 as in compounds 3, 5, 6 and 12. These results introduced new phthalazine derivatives having promising activity which could lead to the development of more potent anticancer agents.

In-Vitro Anticancer Evaluation and Docking Study of Novel Benzo[g] Quinazoline-sulfonamide Derivatives

BACKGROUND

Quinazoline and sulfonamide derivatives are considered to be important classes of drugs due to their wide range of biological activities especially anticancer.

METHODS

A novel series of sulfonamides incorporating benzo[g] quinazolinemoieties 2-19 and sulfonyl containing benzo[g] quinazolinemoieties 20, 21 were designed and synthesized starting from 4- chlorobenzo[g] quinazoline 1. In-vitro screening as anticancer agents was done for the synthesized compounds. Molecular docking study was also performed to explore the binding interactions of the synthesized compounds within the active site of carbonic anhydrase IX (CA IX), which most commonly expressed in some types of cancer cells.

CONCLUSION

The results indicated that the most potent compounds were 2 and 7 showing effectiveness on more than one cell line.

NAD(P)H: quinone oxidoreductase 1 inducer activity of novel 4-aminoquinazoline derivatives

Fourteen novel 4-aminoquinazoline derivatives 2-15 were designed and synthesized. The structure of the newly synthesized compounds was established on the basis of elemental analyses, IR, (1)H-NMR, (13)C-NMR, and mass spectral data. The compounds were evaluated for their potential cytoprotective activity in murine Hepa1c1c7 cells. All of the synthesized compounds showed concentration-dependent ability to induce the cytoprotective enzyme

NAD(P)H

quinone oxidoreductase (NQO1) with potencies in the low- to sub-micromolar range. This approach offers an encouraging framework which may lead to the discovery of potent cytoprotective agents.

Modulatory effects of new curcumin analogues on gamma-irradiation - Induced nephrotoxicity in rats

In the present study, a new series of 2-amino-pyran-3-carbonitrile derivatives of curcumin 2-7 have been synthesized via one-pot simple and efficient protocol, involving the reaction of curcumin 1 with substituted-benzylidene-malononitrile to modify the 1,3-diketone moiety. The structures of the synthesized compounds 2-7 were elucidated by microanalytical and spectral data, which were found consistent with the assigned structures. The nephroprotective mechanism of these new curcumin analogues was evaluated on the post-gamma-irradiation (7 Gy) - induced nephrotoxicity in rats. Activation of Nrf2 by these curcumin analogues is responsible for the amendment of the antioxidant status, impairment of NF-κB signal, thus attenuate the nephrotoxicity induced post-γ-irradiation exposure. 4-Chloro-phenyl curcumin analogue 7 showed the most potent activity. In conclusion, the results of the present study demonstrate a promising role of these new curcumin analogues to attenuate the early symptoms of nephrotoxicity induced by γ-irradiation in rats via activation of Nrf2 gene expression. These new curcumin analogues need further toxicological investigations to assess their therapeutic index.

Synthesis and biological evaluation of novel 2-phenylquinazoline-4-amine derivatives: identification of 6-phenyl-8H-benzo[g]quinazolino[4,3-b]quinazolin-8-one as a highly potent inducer of NAD(P)H quinone oxidoreductase 1

A novel series of quinazoline compounds (2-14) incorporating biologically active heterocyclic moieties were designed and synthesized. The structure of the newly synthesized compounds was recognized on the basis of elemental analyses, IR, 1H-NMR, 13C-NMR and mass spectral data. All compounds were evaluated for their ability to induce the cytoprotective enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1) using a quantitative bioassay and a docking study was performed in the Kelch domain of Keap1 obtained from the Protein Data Bank (PDB ID: 4IQK) to explore the ability of the synthesized compounds to block the Nrf2-binding site of Keap1. All of the synthesized compounds showed concentration-dependent inducer activity with potencies in the low- or sub-micromolar range. Compound 12 was the most potent inducer in this new series, with a concentration that doubles the specific activity of NQO1 (CD value) of 70 nM. The identification of this compound offers a new chemical scaffold for future development of highly potent inducers.

In-Vitro Anticancer Evaluation of Some Novel Thioureido-Benzensulfonamide Derivatives

A novel series of sulfonamide derivatives (14 compounds) bearing thiourea moieties were efficiently synthesized and evaluated for their possible in vitro anticancer activity against four human tumor cell lines. The results indicated that compound 6 was the most potent, showing effectiveness on all the tested cell lines. Compounds 7 and 10 also showed promising results.

Design, Synthesis and Anticancer Evaluation of Novel Quinazoline-Sulfonamide Hybrids

By combining the structural features of quinazoline and sulfonamides, novel hybrid compounds 2–21 were synthesized using a simple and convenient method. Evaluation of these compounds against different cell lines identified compounds 7 and 17 as most active anticancer agents as they showed effectiveness on the four tested cell lines. The anticancer screening results of the tested compounds provides an encouraging framework that could lead to the development of potent new anticancer agents.

Synthesis of novel thiadiazole derivatives as selective COX-2 inhibitors

A novel series of thiadiazole derivatives were designed and synthesized for evaluation as selective COX-2 inhibitors in vitro and were investigated in vivo as anti-inflammatory and analgesic agents against carrageenan-induced rat paw oedema model in irradiated rats.

Synthesis, anticancer and radiosensitizing evaluation of some novel sulfonamide derivatives

In this study, novel series of sulfonamide derivatives were synthesized starting from 2-cyanoacetyl)hydrazono)ethyl)phenyl)benzenesulfonamide 4a and 2-cyanoacetyl)hydrazono)ethyl)phenyl)-4-methylbenzenesulfonamide 4b. Different biologically active moieties as pyrazol, thiophene, pyridine and pyrimidines were introduced in order to investigate their in-vitro anticancer activity, in addition to a novel series of sulfonamide chalcones were synthesized from the reported 4-acetyl-N-(P-tolyl) benzenesulfonamide 3b. The newly synthesized sulfonamide derivatives were characterized by FT-IR, (1)H NMR, (13)C NMR, mass spectroscopy and elemental analyses and were tested for their in-vitro anticancer activity against human tumor liver cell line (HEPG-2). The most potent compounds in this study were compounds 4a, 4b, 5a, 6a, 6b, 8, 9, 11, 13, 18 and 19 which showed higher activity than doxorubicin with IC50 ranging from 11.0 to 31.8 μM. Additionally, eight compounds among the most potent were evaluated for their ability to enhance the cell killing effect of γ-radiation.

Design and synthesis of novel thiophenes bearing biologically active aniline, aminopyridine, benzylamine, nicotinamide, pyrimidine and triazolopyrimidine moieties searching for cytotoxic agents

To discover new bioactive lead compounds for medicinal purposes, herein, (E)-3-(substituted amino)-1-thiophen-2-yl-prop-2-en-1-ones 3-8, aminopyridines 9-11, benzylamine 12, nicotinamide 13, pyrimidines 14, 15, hexanoic acid 16 and triazolopyrimidine 19 were prepared and tested for cytotoxic activity. Results showed that the tested compounds exhibited a remarkable activity, especially compounds 3 and 19 with IC50 values (55.2 and 50.49 microM, respectively) compared to doxorubicin (IC50 = 71.8 microM) as a reference drug.

Synthesis and anti-breast cancer evaluation of novel N-(guanidinyl)benzenesulfonamides

A series of 4-(substituted)-N-(guanidinyl)benzenesulfonamides bearing biologically active pyrazole, pyrimidine and pyridine moieties were prepared and evaluated for their anticancer activity against human tumor breast cell line (MCF7). These sulfonamides showed promising activity with IC50 values ranging from 49.5 to 70.2 μM. The structure-activity relationship of the synthesized compounds was studied. Interestingly, it was found that the most potent compounds in this study were the corresponding 2-cyanoacrylate 3, 3-oxobutanoate 4, pyrazole 6, pyridine 9 and pyrazole 13. Compounds 7 and 8 are nearly as active as Doxorubicin as reference drug with (IC50 values=70.2, 68.1 μM), while compounds 5, 10 and 11 exhibited a moderate activity.

Antiproliferative activity of novel thiophene and thienopyrimidine derivatives

A novel series of newly synthesized thiophene derivatives, ethyl-4,5-dimethyl-2-(3-(3,4,5-trimethoxyphenyl)thioureido)thiophene-3-carboxylate 3, ethyl-2-[(2-(dimethylamino)ethoxy)mercapto)methyleneamino)]-4,5-dimethyl-thiophene-3-carboxylate 9, thienopyrimidines 4, 7, 10-20, triazolothienopyrimidines 5, 6 were prepared and tested for their antiproliferative activity. The structures of the synthesized compounds were confirmed on the basis of elemental analysis, IR, (1)H-NMR, (13)C-NMR and mass spectral data. The results showed that the synthesized compounds were more active on breast cancer than on colon cancer cell lines and the most potent compounds in this study are compounds 3 and 13 which exerted remarkable activity against MDA-MB-231 (breast cancer) and HT-29 (colon cancer) cell lines with IC50 values (40.68, 49.22 μM) for compound 3 and (34.04, 45.62 μM) for compound 13. Also, compounds 4-6, 9 showed a moderate activity against breast cancer cell line, while compounds 15, 19 and 20 showed no activity.

Synthesis, in-vitro anticancer screening and radiosensitizing evaluation of some new N-(quinoxalin-2-yl)benzenesulfonamide derivatives

The objective of this work is to synthesize and investigate the anticancer activity of a new series of sulfaquinoxaline derivatives by incorporating biologically active moieties (thiourethane, thiazole, imidazole, imidazopyrimidine, imidazopyrimido-pyrimidine, thienopyrimidine, benzopyrimidinone, benzothiazole, thiazole and pyridine moieties). All the newly synthesized compounds were evaluated for their in-vitro anticancer activity against human liver cell line (HEPG2). All the tested compounds showed comparable activity to that of the reference drug 5-fluorouracil (IC50=40 µM), and the most potent compounds were found to be compounds 4 and 17 (IC50=4.29 and 11.27 µM, respectively). On the other hand, the most potent compounds 4 and 17 were evaluated as radiosensitizing agents.

Synthesis, in vitro anticancer screening and radiosensitizing evaluation of some new 4-[3-(substituted)thioureido]-N-(quinoxalin-2-yl)-benzenesulfonamide derivatives

Sulfonamides and quinoxaline derivatives possess many types of biological activities and have been recently reported to show substantial antitumor activity. This paper reports the synthesis of novel thioureido sulfaquinoxaline derivatives. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against a human liver cell line (HEPG2) and showed higher activity than the reference drug doxorubicin. 4-(3-(4-Ethylbenzoate) thioureido)-N-(quinoxalin-2-yl)benzenesulfonamide (9) (IC₅₀ = 15.6 μmol L⁻¹), N-(pyridin-2-yl)-4-(3-(4-(N-quinoxalin-2-yl-sulfamoyl)phenyl)thioureido)benzenesulfonamide (10) (IC₅₀ = 26.8 μmol L⁻¹) and N-(quinoxalin-2-yl)-4-(3-(4-(N-thiazol-2-ylsulfamoyl)phenyl)thioureido)benzenesulfonamide (11) (IC₅₀ = 24.4 μmol L⁻¹) were the most potent compared to doxorubicin (IC₅₀ = 71.8 μmol L⁻¹). The most potent compounds 9, 10 and 11 were evaluated as radiosensitizing agents by subjecting the compounds to γ-irradiation (8 kGy).