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The untypical course of reaction between chalcones and benzenesulfonylaminoguanidines led to the new 3-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-2-(1-phenyl-3-arylprop-2-enylideneamino)guanidine derivatives 8–33. The new compounds were tested in vitro for their impact on the growth of breast cancer cells MCF-7, cervical cancer cells HeLa and colon cancer cells HCT-116 by MTT assay. The results revealed that the activity of derivatives is strongly related to the presence of hydroxy group in the benzene ring at the 3-arylpropylidene fragment. The most cytotoxic compounds 20 and 24 displayed mean IC50 values of 12.8 and 12.7 μM, respectively, against three tested cell lines and were almost 3- and 4-fold more active toward MCF-7 and HCT-116 when compared with non-malignant HaCaT cells. Furthermore, compound 24 induced apoptosis in cancer cells and caused a decrease of mitochondrial membrane potential as well as an increase of cells in sub-G1 phase in contrast to its inactive analog 31. The strongest activity against the most sensitive HCT-116 cell line was found for compound 30 (IC50 = 8 μM), which was 11-fold more effective in the growth inhibition of HCT-116 cells than those of HaCaT cells. Based on this fact, the new derivatives may be promising leading structures for the search for agents for the treatment of colon cancer.

In the search for new compounds with antitumor activity, new potential anticancer agents were designed as molecular hybrids containing the structures of a triazine ring and a sulfonamide fragment. Applying the synthesis in solution, a base of new sulfonamide derivatives 20–162 was obtained by the reaction of the corresponding esters 11–19 with appropriate biguanide hydrochlorides. The structures of the compounds were confirmed by spectroscopy (IR, NMR), mass spectrometry (HRMS or MALDI-TOF/TOF), elemental analysis (C,H,N) and X-ray crystallography. The cytotoxic activity of the obtained compounds toward three tumor cell lines, HCT-116, MCF-7 and HeLa, was examined. The results showed that some of the most active compounds belonged to the R1 = 4-trifluoromethylbenzyl and R1 = 3,5-bis(trifluoromethyl)benzyl series and exhibited IC50 values ranging from 3.6 µM to 11.0 µM. The SAR relationships were described, indicating the key role of the R2 = 4-phenylpiperazin-1-yl substituent for the cytotoxic activity against the HCT-116 and MCF-7 lines. The studies regarding the mechanism of action of the active compounds included the assessment of the inhibition of MDM2-p53 interactions, cell cycle analysis and apoptosis induction examination. The results indicated that the studied compounds did not inhibit MDM2-p53 interactions but induced G0/G1 and G2/M cell cycle arrest in a p53-independent manner. Furthermore, the active compounds induced apoptosis in cells harboring wild-type and mutant p53. The compound design was conducted step by step and assisted by QSAR models that correlated the activity of the compounds against the HCT-116 cell line with molecular descriptors.

A series of novel 2-[(4-amino-6-R2-1,3,5-triazin-2-yl)methylthio]-4-chloro-5-methyl-N-(5-R1-1H-benzo[d]imidazol-2(3H)-ylidene)benzenesulfonamides 6&ndash, 49 was synthesized by the reaction of 5-substituted ethyl 2-{5-R1-2-[N-(5-chloro-1H-benzo[d]imidazol-2(3H)-ylidene)sulfamoyl]-4-methylphenylthio}acetate with appropriate biguanide hydrochlorides. The most active compounds, 22 and 46, showed significant cytotoxic activity and selectivity against colon (HCT-116), breast (MCF-7) and cervical cancer (HeLa) cell lines (IC50: 7&ndash, 11 &micro, M, 15&ndash, 24 &micro, M and 11&ndash, 18 &micro, M), respectively. Further QSAR (Quantitative Structure&ndash, Activity Relationships) studies on the cytotoxic activity of investigated compounds toward HCT-116, MCF-7 and HeLa were performed by using different topological (2D) and conformational (3D) molecular descriptors based on the stepwise multiple linear regression technique (MLR). The QSAR studies allowed us to make three statistically significant and predictive models for them. Moreover, the molecular docking studies were carried out to evaluate the possible binding mode of the most active compounds, 22 and 46, within the active site of the MDM2 protein.

To learn more about the structure&ndash, activity relationships of (E)-3-(5-styryl-1,3,4-oxadiazol-2-yl)benzenesulfonamide derivatives, which in our previous research displayed promising in vitro anticancer activity, we have synthesized a group of novel (E)-5-[(5-(2-arylvinyl)-1,3,4-oxadiazol-2-yl)]-4-chloro-2-R1-benzenesulfonamides 7-36 as well as (E)-4-[5-styryl1,3,4-oxadiazol-2-yl]benzenesulfonamides 47-50 and (E)-2-(2,4-dichlorophenyl)-5-(2-arylvinyl)-1,3,4-oxadiazols 51-55. All target derivatives were evaluated for their anticancer activity on HeLa, HCT-116, and MCF-7 human tumor cell lines. The obtained results were analyzed in order to explain the influence of a structure of the 2-aryl-vinyl substituent and benzenesulfonamide scaffold on the anti-tumor activity. Compound 31, bearing 5-nitrothiophene moiety, exhibited the most potent anticancer activity against the HCT-116, MCF-7, and HeLa cell lines, with IC50 values of 0.5, 4, and 4.5 &micro, M, respectively. Analysis of structure-activity relationship showed significant differences in activity depending on the substituent in position 3 of the benzenesulfonamide ring and indicated as the optimal meta position of the sulfonamide moiety relative to the oxadizole ring. In the next stage, chemometric analysis was performed basing on a set of computed molecular descriptors. Hierarchical cluster analysis was used to examine the internal structure of the obtained data and the quantitative structure&ndash, activity relationship (QSAR) analysis with multiple linear regression (MLR) method allowed for finding statistically significant models for predicting activity towards all three cancer cell lines.

A bstract A series of new N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1H-pyrazol-1-yl)amidine derivatives have been synthesized and evaluated in vitro by MTT assays for their antiproliferative activity against cell lines of colon cancer HCT-116, cervical cancer HeLa and breast cancer MCF-7. The studied compounds display selective activity mainly against HCT-116 and HeLa cells. Thus, five compounds show selective cytotoxic effect against HCT-116 (IC50 = 3–10 μM) and HeLa (IC50 = 7 μM). Importantly, the noticed values of IC50 for four compounds are almost 4-fold lower for HeLa than non-malignant HaCaT cells. More-in-depth biological research revealed that the treatment of HCT-116 and HeLa with active compound resulted in increased numbers of cells in sub-G1 phase in a time dependent manner, while non-active derivative does not influence cell cycle. Metabolic stability assays using liver microsomes and NADPH provide important information on compounds susceptibility to phase 1 biotransformation reactions.

Rising resistance of pathogenic bacteria reduces the options of treating hospital and non-hospital bacterial infections. There is a need to search for newer chemotherapies that will show antimicrobial ability against planktonic cells as well as bacterial biofilms. We have synthesized a series of N-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)amides, namely, molecular hybrids, which include a 2-mercaptobenzenosulfonamide fragment and either cinnamic or cyclohexylpropionic acid residues. The antimicrobial activity of compounds 8‒17 was evaluated on Gram-positive, Gram-negative bacteria and fungal species. Experiments took into account investigation of antibacterial activity against planktonic cells as well as biofilms. Compounds 8‒17 showed high bacteriostatic activity against staphylococci, with the most active molecules 10 and 16 presenting low MIC values of 4&ndash, 8 &mu, g/mL against reference methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains as well as clinical isolates. Compounds 10 and 16 also showed an ability to inhibit biofilms formed by MRSA and MSSA. The potential of 10 and 16 as antibiofilm agents was supported by cytotoxicity assays that indicated no cytotoxic effect either on normal cells of human keratinocytes or on human cancer cells, including cervical, colon, and breast cancer lines.

A new series of N-(aryl/heteroaryl)-2-chlorobenzenesulfonamide derivatives 4-21 have been synthesized, and evaluated at the National Cancer Institute (USA) for their in vitro activities against a panel of 60 different human cancer cell lines. Among them, compounds 16, 20 and 21 exhibited remarkable cytotoxic activity against numerous human cancer cell lines. We found that sulfonamide derivative 21 appeared to be more selective than compounds 16 and 20. In comparison to compounds 16 and 20 it showed higher cytotoxic activity against A549 non-small cell lung adenocarcinoma and HCT-116 colon carcinoma cells and was less toxic to HEK-293 human embryonic kidney cells and HaCaT immortalized human keratinocytes. Treatment of A549 and HCT-116 cells with compound 21 resulted in the G0/G1-cell cycle arrest with a concomitant increase in p53 and p21 protein levels. Moreover, compound 21 led to ATP depletion and disruption of the mitochondrial membrane potential in both studied cell lines. Our results suggest that 2,4-dichloro-N-(quinolin-8-yl and/or 1H-indazol-7-yl)benzenesulfonamides serve as novel promising anticancer agents.

A series of N-(aryl/heteroaryl)-4-(1H-pyrrol-1-yl)benzenesulfonamides were synthesized from 4-amino-N-(aryl/heteroaryl)benzenesulfonamides and 2,5-dimethoxytetrahydrofuran. All the synthesized compounds were evaluated for their anticancer activity on HeLa, HCT-116, and MCF-7 human tumor cell lines. Compound 28, bearing 8-quinolinyl moiety, exhibited the most potent anticancer activity against the HCT-116, MCF-7, and HeLa cell lines, with IC50 values of 3, 5, and 7 µM, respectively. The apoptotic potential of the most active compound (28) was analyzed through various assays: phosphatidylserine translocation, cell cycle distribution, and caspase activation. Compound 28 promoted cell cycle arrest in G2/M phase in cancer cells, induced caspase activity, and increased the population of apoptotic cells. Relationships between structure and biological activity were determined by the QSAR (quantitative structure activity relationships) method. Analysis of quantitative structure activity relationships allowed us to generate OPLS (Orthogonal Projections to Latent Structure) models with verified predictive ability that point out key molecular descriptors influencing benzenosulfonamide’s activity.

A series of novel N-acyl-4-chloro-5-methyl-2-(R¹-methylthio)benzenesulfonamides 18-47 have been synthesized by the reaction of N-[4-chloro-5-methyl-2-(R¹-methylthio) benzenesulfonyl]cyanamide potassium salts with appropriate carboxylic acids. Some of them showed anticancer activity toward the human cancer cell lines MCF-7, HCT-116 and HeLa, with the growth percentages (GPs) in the range from 7% to 46%. Quantitative structure-activity relationship (QSAR) studies on the cytotoxic activity of N-acylsulfonamides toward MCF-7, HCT-116 and HeLa were performed by using topological, ring and charge descriptors based on the stepwise multiple linear regression technique (MLR). The QSAR studies revealed three predictive and statistically significant models for the investigated compounds. The results obtained with these models indicated that the anticancer activity of N-acylsulfonamides depends on topological distances, number of ring system, maximum positive charge and number of atom-centered fragments. The metabolic stability of the selected compounds had been evaluated on pooled human liver microsomes and NADPH, both R¹ and R² substituents of the N-acylsulfonamides simultaneously affected them.

A series of novel 4-substituted-N-(phenylcarbamoyl)-3-pyridinesulfonamides 11-27 have been synthesized by the reaction of 4-substituted pyridine-3-sulfonamides 2-10 with the appropriate aryl isocyanates in presence of potassium carbonate. The in vitro anticancer activity of compounds 11, 12, 14-21 and 24-26 was evaluated at the U.S. National Cancer Institute and in light of the results, some structure-activity relationships were discussed. The most prominent compound, N-[(4-chlorophenyl)carbamoyl]-4-[4-(3,4-dichlorophenyl)piperazin-1-yl]pyridine-3-sulfonamide (21) has exhibited a good activity profile and selectivity toward the subpanels of leukemia, colon cancer and melanoma, with average GI50 values ranging from 13.6 to 14.9 µM.

A series of novel 2-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)-1-(6-substituted-4-chloro-1,3,5-triazin-2-ylamino)guanidine derivatives 9–20 have been synthesized by substitution of chlorine atom at the 1,3,5-triazine ring in compounds 5–8 with 3- or 4-aminobenzenesulfonamide and 4-(aminomethyl)benzenesulfonamide hydrochloride. All the synthesized compounds were evaluated for their inhibitory activity toward hCA I, II, IX and XII as well as anticancer activity against HeLa, HCT-116 and MCF-7 human tumor cell lines. The investigated compounds showed weak inhibitory potency against the human CA I, while activity toward hCA II was differentiated and depended on structure of inhibitor (KI: 5.4–933.1 nM). Compounds containing the 4-sulfamoylphenyl moiety (9–12) exhibited the strongest inhibitory activity against hCA IX with KI values from 37.1 to 42.9 nM, as well as against hCA XII in range of 31–91.9 nM. The most promising compound 12 (KI = 41 nM) showed the highest selectivity toward hCA IX versus hCA I (hCA I/hCA IX = 18) and hCA II (hCA II/hCA IX = 4). Compound 12 displayed prominent cytotoxic effect selectively toward HeLa cancer cells (IC50 = 17 μM) and did not exhibit toxicity to the non-cancerous HaCaT cells. In silico analysis suggested that despite the lack of a single binding pose, the selective affinity is conferred by specific interactions with an arginine moiety, as well as better-defined binding modes within the active site.

Sulfonylureas have been commonly used since the 1950s as antihypoglycemic (e.g., tolbutamide, glipizide, glimepiride) and diuretics drugs (torasemide). Preclinical studies towards antineoplastic activity of sulfonyloureas led to recognize among them a group of diarylsulfonylureas (DSU) (e.g. LY-181984, Sulofenur and LY‑295501) with activity against a broad spectrum of syngeneic rodent solid tumors and human tumor xenografts [1]. Continuing our previous studies, in which we have shown a significant potential for antitumor activity of 1-(4-substituted pyridine-3-sulfonyl)-3-phenylureas [2], we have undertaken the synthesis and evaluation of cytostatic activity of novel series of N-{[4-(1,2,3-triazol)pyridin-3-yl]sulfonyl}urea derivatives. To provide easy functionalization of substituent at the position 4 of the pyridinesulfonamide scaffold, which have a significant influence on the antitumor activity [2.3], we started from 4-(2-propyn-1-ylthio/amino)pyridine-3-sulfonamides and, using the copper-catalyzed azide-alkyne cycloaddition (CuAAC), introduced 1,4-disubstituted 1,2,3-triazole ring. The primary sulfonamides thus obtained were next treated with various isocyanates to give a series of desired sulfonylurea derivatives. The structures of all compounds were confirmed with IR and NMR spectroscopy and elemental analyses. All compounds were submitted to test their effects on growth of human cancer cell lines: colon cancer HCT-116, breast cancer MCF-7 and cervical cancer HeLa. Cell viability was measured using MTT assay after 72 h of incubation with tested compound in concentration 1 – 100 μM. References: Pasello G, et al. Oncologist 2013; 18: 1118–1125. Szafranski K, Slawinski J. Molecules. 2015; 20; 12029–12044. Slawinski J, et al. Eur J Med Chem. 2013;69:701–10.

A series of new 2-(2-alkylthiobenzenesulfonyl)-3-(phenylprop-2-ynylideneamino)guanidine derivatives have been synthesized and evaluated in vitro by MTT assays for their antiproliferative activity against cell lines of colon cancer HCT-116, cervical cancer HeLa and breast cancer MCF-7. The obtained results indicated that these compounds display prominent cytotoxic effect. The best anticancer properties have been observed for derivatives 44 (IC 50 = 6–18 μM) and 45 (IC 50 = 8–14 μM). Very good results of antiproliferative assays have been also shown for compounds 26 , 36 , and 46 and noticeable anticancer profile has been found for set of derivatives 34 – 39 . Based on results of MTT assays the structure-activity relationships have been drawn. More in-depth biological research revealed that compounds 26 , 33 , 37 , 39 , 41 and 43 display cytotoxic effect only against cancer cells and do not inhibit the growth of non-malignant HaCaT cells. Furthermore, the novel series of derivatives have shown good metabolic stability, especially among the pharmacologically active compounds. To obtain a deeper insight into the molecular description of compounds activity the QSAR studies have been applied. Support vector machines (SVM) have been used to developed QSAR models for predicting the anti-proliferative activity of novel derivatives. The obtained SVM models have shown prognostic ability for HCT-116 and HeLa cell lines and as a result these models may be useful for further development of structurally similar derivatives with better biological properties.

A series of novel N 4 -substituted 4-(2-aminoethyl)benzenesulfonamides 5 – 17 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), that is the cytosolic CA I and II, and tumor-associated isozymes CA IX and XII. Against the human CA I investigated compounds displayed K I values from 96.3 to 3520 nM, toward hCA II at range of 18.1–2055 nM, while against hCA IX ranging from 5.9 to 419 nM and against hCA XII in the range of 4.0–414 nM. The very good inhibitory activity against tumor-associated hCA IX and hCA XII was found. The six new compounds displayed a powerful inhibitory potency toward hCA IX ( K I = 5.9–10.7 nM) in comparison with the clinically used CAIs AAZ , MZA , EZA , DCP and IND (24–50 nM). The most potent hCA IX and hCA XII inhibitors 11 and 12 ( K I : 5.9 and 6.2 nM for hCA IX and 4.3 and 4.0 nM for hCA XII, respectively) belonged to the compounds with cationic character and presented meaningful affinity to the transmembrane isoforms hCA IX and XII than to physiologically dominant isozymes hCA I and II with the selectivity ratios hCA IX versus hCA II and hCA XII versus hCA II for 11 and 12 in the range of 10–15.

A series of novel 5-substituted 2,4-dichlorobenzenesulfonamides 5a–c, 6a–d, 7a–j and 10a–i have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and tumor-associated isozymes CA IX and XII. Against the human CA I investigated compounds displayed KI values from 349 to 7355 nM, toward hCA II at range of 6.9 to 164 nM, while against hCA IX ranging from 2.8 to 76 nM and against hCA XII in the range of 2.7 to 95 nM. The excellent inhibitory activity against tumor-associated hCA IX was found. The twenty one new compounds displayed a powerful inhibitory potency toward hCA IX (KI = 2.8–21.7 nM) in comparison with the clinically used CAIs AAZ, MZA, EZA, DCP and IND (24–50 nM). Among them the most potent hCA IX inhibitor 7b (KI = 2.8 nM) was 8.5-fold stronger than IND (KI = 24 nM). Toward tumor-associated hCA XII compounds 6c and 10a (KI = 2.7 and 2.8 nM, respectively) showed a better inhibitory potency than reference sulfonamides MZA and IND (KI = 3.4 nM).

A series of novel heterocyclic 4-substituted pyridine-3-sulfonamides 2–13, 15–20 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and tumor-associated isozymes CA IX and XII. Against the human isozymes hCA I the new compounds showed KI values in the range 169–5400 nM, toward hCA II in range 58.5–1238 nM, against hCA IX in range 19.5–652 nM and against hCA XII in the range of 16.8–768 nM. Compounds 15–19 representing 4-(1H-pyrazol-1-yl)-3-pyridinesulfonamide derivatives showed good hCA IX inhibitory efficacy with KI = 19.5–48.6 nM comparable or more effective than clinically used sulfonamides: AAZ, MZA, EZA, DCP, IND (KI = 24–50 nM). Anticancer evaluation at a single dose 10 μM, against a panel of 60 human tumor cell lines, was performed at the US National Cancer Institute, on compounds 2, 3, 5–13, 16, 17, 19, 20. Among them 6 bearing 4-(3,4,-dichlorophenyl)piperazine moiety showed broad spectrum of growth inhibition in the range 25–89% over 26 cell lines representing all tumors subpanels.

The reactions of 4-substituted 3-pyridinesulfonamides 1a, 1b, 1c, 1d, 1e with benzenesulfonyl chlorides 2a, 2b, 2c, 2d, 2e, 2f in acetonitrile were investigated. Depending on the structure of arylsulfonyl chlorides and the reaction conditions the following four types of products were obtained in good yields: 3-sulfamoyl-4-R-1-arylpyridinium chlorides 3, 4, 5, 6, 7, 8; 1,10-bis(3-nitrobenzenesulfonylimino)deca-2,4,6,8-tetraene-2,9-disulfonamides 9, 10, 11, 12; 1-substituted 1,4-dihydro-4-oxo-3-pyridinesulfonamides 13, 14; and 4-methoxy-3-[N-(2,5-dichlorophenyl)sulfonyl] sulfonamidates 15 and 16. The mechanisms of these reactions were discussed.

3-Amino-1,1-dioxopyrido[4,3- e ]-1,4,2-dithiazine has been synthesized and applied to the synthesis of 3-amino-2-(4-thioxo-1,4-dihydropyridin-3-ylsulfonyl)guanidine. The reaction of the aminoguanidine with the appropriate 1,2-diarylethane-1,2-diones afforded 2,3-diaryl-9,9-dioxo-1 H -9-thia-1,4,4a,7,10-pentaazaphenanthrene-2-ol derivatives. The structure of these compounds, which represent a novel heterocyclic ring system, was confirmed on the basis of elemental analysis and spectroscopic data including COSY, NOESY, ROESY, HSQC, and HMBC.

A series of novel 2-benzylthio-4-chloro-5-(5-substituted 1,3,4-oxadiazol-2-yl)benzenesulfonamides ( 4 – 27 ) have been synthesized as potential anticancer agents. MTT assay was carried out to determine the cytotoxic activity against three human cancer cell lines: colon cancer HCT-116, breast cancer MCF-7 and cervical cancer HeLa as well as to determine the influence on human keratinocyte cell line HaCaT. Relatively high (IC 50 : 7–17 μM) cytostatic activity and selectivity against HeLa cell line was found for compounds 6, 7, 9–11 and 16. While compounds 23 – 27 bearing styryl moieties attached to a 1,3,4-oxadiazole ring at position 5, exhibited significant activity against two and/or three cancer cell lines with IC 50 : 11–29 μM. Further quantitative structure-activity relationships based on molecular descriptors calculated by DRAGON software, were investigated by Orthogonal Projections to Latent Structures (OPLS) technique and Variable Influence on Projection (VIP) analysis. Considering molecular descriptors with the highest influence on projection (highest VIP values) lipophilicity of tested compounds was pointed as main factor affecting activity towards HCT-116 cell line, while structural parameters associated with presence of styryl substituent in position 5 of 1,3,4-oxadiazole ring were identified as essential for activity towards MCF-7 breast cancer. In vitro tests for metabolic stability in the presences of pooled human liver microsomes and NADPH showed that some of the most active compounds 26 and 27 presented favorable metabolic stability with t 1/2 in the range of 28.1–36.0 min.

A series of novel 5-substituted 2-(arylmethylthio)-4-chloro-N-(5-aryl-1,2,4-triazin-3-yl) benzenesulfonamide derivatives 27–60 have been synthesized by the reaction of aminoguanidines with an appropriate phenylglyoxal hydrate in glacial acetic acid. A majority of the compounds showed cytotoxic activity toward the human cancer cell lines HCT-116, HeLa and MCF-7, with IC50 values below 100 μM. It was found that for the analogues 36–38 the naphthyl moiety contributed significantly to the anticancer activity. Cytometric analysis of translocation of phosphatidylserine as well as mitochondrial membrane potential and cell cycle revealed that the most active compounds 37 (HCT-116 and HeLa) and 46 (MCF-7) inhibited the proliferation of cells by increasing the number of apoptotic cells. Apoptotic-like, dose dependent changes in morphology of cell lines were also noticed after treatment with 37 and 46. Moreover, triazines 37 and 46 induced caspase activity in the HCT-116, HeLa and MCF-7 cell lines. Selected compounds were tested for metabolic stability in the presence of pooled human liver microsomes and NADPH, both R2 and Ar = 4-CF3-C6H4 moiety in 2-(R2-methylthio)-N-(5-aryl-1,2,4-triazin-3-yl)benzenesulfonamides simultaneously increased metabolic stability. The results pointed to 37 as a hit compound with a good cytotoxicity against HCT-116 (IC50 = 36 μM), HeLa (IC50 = 34 μM) cell lines, apoptosis-inducing activity and moderate metabolic stability.

A series of novel 3-pyridinesulfonamide derivatives (2-5, 9-11 and 13-15) have been synthesized and investigated as inhibitors of five isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), that is, the cytosolic ubiquitous CA I and II, and isozymes CA IX and XII (cancer-associated), and XIV. Against the human isozyme hCA I the new compounds showed K(I)s in the range of 0.089-251 μM, whereas toward hCA II, K(I)s = 50.5-487 nM. Isozyme hCA IX was inhibited with K(I)s in the range of 5.2-18.3 nM, while hCA XII with K(I)s = 6.0-16.4 nM, and hCA XIV with K(I)s = 76.4-152.0 nM. All of the new compounds 2-5, 9-11 and 13-15 showed excellent hCA IX inhibitory efficacy, with K(I)s = 5.2-18.3 nM, being much more effective as compared to the clinically used AAZ, MZA, EZA, DCP and IND (K(I)s = 24-50 nM).

Several N,N-disubstituted aromatic amines (3a–g) was obtained in very good yield by the reaction of adequate doubly activated aromatic or heteroaromatic halides (1a–e) with N,N-disubstituted formamides (2a–c). Analogously, starting from 4-chloro-3-pyridinesulfonamide, the appropriate 4-dialkylamino-1H +-pyridinium-3-(N-formyl)sulfonamidates (5a,b) were obtained in 52–60% yield. Mechanisms of the reactions are discussed.

Potassium 1,1-dioxopyrido[4,3-e]-1,4,2-dithiazine-3-thiolate 2 has been synthesized and applied to the syntheses of 7H-1,1-dioxopyrido[4,3-e]-1,4,2-dithiazolium-3-thiolate 3 and 3-methylthiopyrido[4,3-e]-1,4,2-dithiazine 1,1-dioxide 4 which provided easy access to a variety of its 3-amino derivatives 5-10. Hydrazinolysis of 7, 8 and 10 afforded the corresponding 3-amino-2-(1,4-dihydro-4-thioxopyrid-3-ylsulfonyl)guanidines 11-13. Subsequent reaction of 12 with 4-chlorobenzaldehyde gave condensation product 14. 1,4-Dihydro-2-thioxopyridine-3-sulfonamide 15 was also prepared from the potassium salt 2 upon alkaline hydrolysis, whereas alkylation of 15 gave the appropriate S-substituted derivatives 16-19 or S,N-disubstituted compounds 20-21.

A new series of N -(6-chloro-1,1-dioxo-1,4,2-benzodithiazin-3-yl)arylsulfonamides 23 – 48 have been synthesized as potential anticancer agents. All compounds were screened for their cytotoxic activity against six human tumor cell lines. The selected compounds 23 – 27 , 30 , 31 , 33 , 35 , 38 , 42 , 45 , and 46 were further tested at the US National Cancer Institute for their in vitro activities against a panel of 53–59 human tumor cell lines. The compounds 23 – 26 , 30 , 31 , 33 , 38 , 42 , 45 , and 46 showed 50% growth inhibitory activity in low micromolar concentration (GI 50 = 0.03–4.9 μM) against one or more human tumor cell lines ( Table 3 ). The prominent compound with remarkable activity (GI 50 = 0.03 μM, TGI = 1.3 μM) and selectivity toward melanoma UACC-257 cell line was N -(6-chloro-7-cyano-1,1-dioxo-1,4,2-benzodithiazin-3-yl)- N -(phenyl)-5-bromothiophene-2-sulfonamide 46 .

Three series of novel 2-benzylthio-4-chloro-5-R1-benzenesulfonamides bearing the N-(benzoxazol-2-yl) (10–19), N-(benzothiazol-2-yl) (20–21) or N-(1,3-dihydro-2H-benzimidazol-2-ylidene) (22–25) moiety were synthesized by reacting N-(2-benzylthio-4-chloro-5-R1-benzenesulfonyl)cyanamide potassium salts (5–9) with 2-aminophenols, 2-aminothiophenol and o-phenylenediamines, respectively. Compounds with carbamoyl substituent at position 5 (14–16, 21 and 25, R1 = CONH2) were further dehydrated to the corresponding nitriles (26–30, R1 = CN). The in vitro antitumor activity of the compounds obtained was determined at the National Cancer Institute (NCI), and the structure–activity relationships were discussed. N-(2-benzoxazolyl)-2-benzylthio-4-chloro-5-(4-fluorophenylcarbamoyl)benzenesulfonamide (18) is the prominent of the compounds due to its remarkable activity and selectivity toward non-small cell lung cancer (NCI-H522) and melanoma (SK-MEL-2) cell lines (GI50 = 0.1 μM, TGI = 0.5–0.6 μM).

The syntheses of S-(5-chloro-4-methyl-2-sulfamoylphenyl)alkanethio (or benzothio)hydrazonates (3a-3o) and potassium S-(5-chloro-2-cyanoamidatesulfonyl-4-methylphenyl)alkanethio (or benzothio)hydrazonates (4-10) are described. The compounds 3e, 3i-3o, 7 and 8 were screened at the National Cancer Institute (NCI) for their activities against a panel of 59 tumor cell lines and relationships between structure and antitumor activity in vitro are discussed. The compounds 3e, 3j, 3l-3o and 7 exhibited reasonable activity against numerous human tumor cell lines. The prominent compound 3l showed significant activity against some cell lines of leukemia (SR), melanoma (SK-MEL-5), CNS cancer (SF-539), ovarian cancer (OVCAR-3, OVCAR-4) and breast cancer (MDA-MB-231/ACTT) (GI50 values in the range 0.3-0.9 microM). Furthermore, compound 8 exhibited the high selectivity against renal cancer (A498) cells (GI500.01 microM, TGI = 2.3 microM and LC50 = 35.7 microM).

A series of 6′-chloro-1′,1′-dioxo-2′H-spiro[benzo[d][1,3,7]oxadiazocine-4,3′-(1,4,2-benzodithiazine)]-2,6(1H,5H)-dione derivatives 2a, 2b and 3a, 3b have been synthesized starting from 3-aminobenzodithiazines 1a, 1b and isatoic anhydride. Subsequent reactions of 2a with 3-chlorophenyl isocyanate gave condensation products 4 and 5. Compound 2a was also converted into 3-(2-aminobenzamido)-6-chloro-7-methyl-1,1-dioxo-1,4,2-benzodithiazine derivatives 6, 7, 8, 9, 10. The mechanisms of the reactions are discussed.

A series of novel N-substituted N'-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)guanidines 9-41 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and cancer-associated isozymes CA IX and XII. Against the human CA I investigated compounds showed KI in the range of 87-6506 nM, toward hCA II ranging from 7.8 to 4500 nM, against hCA IX in the range of 4.7-416 nM and against hCA XII at range of 0.96-540 nM. Compounds 10, 12-14, 16, 18-20, 24-26, 31 and 32 exhibited a powerful inhibitory potency toward hCA IX (K(I) = 4.7-21 nM) in comparison to the reference sulfonamides AAZ, MZA, EZA, DCP and IND (K(I) = 24-50 nM). Compound 14 was the most potent inhibitor of hCA I (K(I) = 87 nM), hCA IX (K(I) = 4.7 nM) and hCA XII (K(I) = 0.96 nM), while 26 was the most effective inhibitor of hCA II (K(I) = 7.8 nM). The most promising compound 32 exerted the highest selectivity ratios toward hCA IX versus hCA I (hCA I/hCA IX = 261) and hCA II (hCA II/hCA IX = 26). The in vitro antitumor activity of compounds 10, 13, 14, 21, 22, 25, 32, 38 and 41 was evaluated at the US National Cancer Institute (NCI) against a panel of 60 human tumor cell lines. The most active antitumor agents 21 and 25, inhibiting 32-35 human tumor cell lines with GI₅₀ in the range of 2.1-5.0 μM also showed relatively high inhibitory activity toward hCA IX and XII with KI from 18 to 40 nM.

A series of novel 1-substituted 1,4-dihydro-4-oxo-3-pyridinesulfonamides 4-6, 9-17 and 21-31 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and cancer-associated isozymes CA IX and XII. Against the human isozymes hCA I the new compounds showed K(I)s in the range of 224-4830 nM, whereas toward hCA II, K(I)s = 318-873 nM. Isozyme hCA IX was inhibited with K(I)s = 11.8-93.4 nM, and hCA XII with 23.5-82.3 nM. Compounds 12-14, 27 and 29-31 have an activity against hCA I (K(I)s = 224-889 nM) which is comparable to the clinically used sulfonamide DCP (K(I)s = 1200 nM). Several of new compounds, including 9, 10, 21, 24, 26-28 and 30 have an activity against hCA IX (K(I)s = 11.8-38.6 nM) which is comparable or more effective than the clinically used sulfonamides AAZ, MZA, EZA, DCP and IND (K(I)s = 24-50 nM). Compounds 9, 10, 13, 21-23, 26 and 27 were also very effective hCA XII inhibitors, with inhibition constants ranged from 23.5 to 47.2 nM comparable or more effective than sulfonamides EZA (K(I)s = 22 nM) or DCP (K(I)s = 50 nM), respectively.

Twenty four 1-[2-alkylthio-5-(azol-2 or 5-yl)-4-chlorobenzenesulfonyl]-3-hydroxyguanidines 6a-x have been synthesized in order to evaluate their biological activity. Compounds 6a, 6c, 6d, 6f, 6g, 6i-p, 6r-t, and 6v-x were tested for their in vitro anticancer activity at the US National Cancer Institute. The highest in vitro anticancer activity was found for compounds 6d, 6g and 6k with GI(50) average value in the range 1.62-1.86 μM, and TGI mean values 3.72-4.47 μM, whereas the remaining compounds showed broad spectrum of anticancer activity at low micromolar GI(50) level against all tested cancer cell lines. These results were subjected to CoMSIA analysis to establish quantitative structure-activity relationships. The results evidence that potency of these compounds correlates mainly with hydrophobic and polar surface properties of substituents located both at 2 and 5 positions of 1-(4-chlorobenzenesulfonyl) moiety of investigated 3-hydroxyguanidine series.

Few series of novel 4-chloro-2-mercaptobenzenesulfonamides have been synthesized by the reactions of N-(benzenesulfonyl)cyanamide potassium salts 7–15 with corresponding hydrazinecarbodithioic acid esters, 1-substituted carbothioic acid hydrazides, methyl 3-aminothiophene-2-carboxylate, methyl 2-aminobenzoate, 2-aminophenol or 2-aminothiophenol. The synthesized compounds (16–49) were screened in vitro for their antibacterial activity. Some of the tested compounds 16, 17, 23, 24, 31, 32 and 48 showed the promising activity against many of anaerobic Gram-positive bacteria strains.

A new amination method by treating substituted aromatic or heteroaromatic chlorides with formamides is developed.

A series of 1-substituted 1,4-dihydro-4-oxo-3-pyridinesulfonamide (2-16) have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), that is the cytosolic ubiquitous CA I and II, and cancer-associated isozymes CA IX and XII. Against the human isozymes hCA I the new compounds showed inhibition constants in the range of 1.09-12.1 microM, against hCA II in the range of 50.5-172 nM, against hCA IX in the range of 5.2-118 nM, and against hCA XII in the range of 8.7-381 nM, respectively. Compounds 2, 3, 5-9, 11, 13 and 14 showed excellent hCA IX inhibitory efficacy, with K(I)s = 5.2-11.0 nM, being much more effective as compared to the clinically used sulfonamides AAZ, MZA, EZA, DCP and IND (K(I)s = 24-50 nM). Compounds 2, 3, 5-9, 11 and 13 were also very effective hCA XII inhibitors (K(I)s = 8.7-45.2 nM) which are comparable or more effective than those clinically used EZA and DCP (K(I)s = 22 and 50 nM), respectively.

A series of novel 4-substituted-3-pyridinesulfonamides ( 2 – 27 and 31 – 33 ) have been synthesized and investigated as inhibitors of five isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), that is, the cytosolic, ubiquitous isozymes CA I and II, and transmembrane isozymes CA IX, XII (cancer-associated) and XIV. Against the human isozymes hCA I, the new compounds showed inhibition constants in the range of 0.078–11.7 μM, against hCA II in the range of 9.9–140 nM, against hCA IX in the range of 4.6–313 nM, against hCA XII in the range of 3.4–21.6 nM, and against hCA XIV in the range of 50.9–160 nM, respectively. Compounds 4 , 6 , 7 , 9 , 11 – 14 , 19 , 20 , 22 – 24 , 26 , 27 , 31 and 32 showed excellent hCA IX inhibitory efficacy, with inhibition constants of 4.6–12.0 nM, being much more effective as compared to the clinically used sulfonamides AAZ , MZA , EZA , DCP and IND . 4-[ N ′-(6-Chloro-7-cyano-1,1-dioxo-1,4,2-benzodithiazin-3-yl)hydrazino]-3-pyridinesulfonamide ( 31 ) is the prominent of the compounds due to its remarkable inhibitory activity toward hCA I ( K I s = 0.078 μM), hCA IX ( K I s = 7.2 nM) and hCA XII ( K I s = 3.4 nM).

Novel 3-amino-2-(4-chloro-2-mercaptobenzenesulfonyl)guanidine derivatives have been synthesized as potential anticancer agents. The in vitro antitumor activity of these compounds has been evaluated in the US National Cancer Institute (NCI), and relationships between structure and antitumor activity are discussed. The prominent compound was 1-allyl-2-[4-chloro-5-(4-chlorophenylcarbamoyl)-2-methylthiobenzenesulfonyl]-3-(5-nitrofurfurylideneamino)guanidine ( 8 ) with remarkable activity against 21 human tumor cell lines representing leukemia, lung, colon, melanoma, ovarian, renal, prostate and breast (GI 50 = 0.3–3.0 μM), and selectivity toward leukemia RPMI-8226 cell line (GI 50 = 0.3 μM, TGI = 1.4 μM).

A series of novel 3-aroyl-2,3-dihydro-1,1-dioxo-1,4,2-benzodithiazines 15 – 28 as potential HIV-1 integrase (IN) inhibitors have been synthesized by the reduction of 3-aroyl-1,1-dioxo-1,4,2-benzodithiazines 1 – 14 with benzenesulfonyl hydrazide. All the compounds 15 – 28 inhibited IN mediated strand transfer reaction with IC 50 values ranging from 3 to 30 μM. The 3-(4-bromobenzoyl)-6-chloro-7-methyl-2,3-dihydro-1,1-dioxo-1,4,2-benzodithiazine 17 with the IC 50 values of 4 ± 1 and 3 ± 1 μM for 3′-processing and strand transfer, respectively, was the most potent. Compound 17 as well its analogues were 5–20-fold less potent in Y99S and H114A mutants, implicating these residues as potential drug-binding site. This is a first report implicating Y99S and H114A of IN core domain in drug-binding interactions.

Several 4-chloro-N-(4-oxopyrimidin-2-yl)-2-mercaptobenzenesulfonamide derivatives 13-28 and 35-44 have been synthesized and tested as potential HIV-1 integrase (IN) inhibitors. Compounds 15-17, 19, 21-28, 36 and 41 inhibited IN with IC(50) values in the range of 3.3-63.0 microM. The compounds 13, 15, 16, 21-24 and 26-28 were further tested at the US National Cancer Institute for their in vitro activity against a panel of 53-57 human tumor cell lines. The compounds 26-28 were inactive, whereas the other compounds exhibited high or reasonable activity (GI(50)