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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.

In this work, a target-based drug screening method is proposed exploiting the synergy effect of ligand-based and structure-based computer-assisted drug design. The new method provides great flexibility in drug design and drug candidates with considerably lower risk in an efficient manner. As a model system, 45 sulphonamides (33 training, 12 testing ligands) in complex with carbonic anhydrase IX were used for development of quantitative structure-activity-lipophilicity (property)-relationships (QSPRs). For each ligand, nearly 5,000 molecular descriptors were calculated, while lipophilicity (logkw) and inhibitory activity (logKi) were used as drug properties. Genetic algorithm-partial least squares (GA-PLS) provided a QSPR model with high prediction capability employing only seven molecular descriptors. As a proof-of-concept, optimal drug structure was obtained by inverting the model with respect to reference drug properties. 3509 ligands were ranked accordingly. Top 10 ligands were further validated through molecular docking. Large-scale MD simulations were performed to test the stability of structures of selected ligands obtained through docking complemented with biophysical experiments.

The two β-carbonic anhydrases (CAs, EC 4.2.1.1) from the pathogenic bacterium Brucella suis, BsuCA1 and BsuCA2, were investigated for their inhibition profile with a series of pyridine-3-sulphonamide derivatives incorporating 4-hetaryl moieties. BsuCA1 was effectively inhibited by these sulphonamides with inhibition constants ranging between 34 and 624 nM. BsuCA2 was less sensitive to these inhibitors, with KIs in the range of 62 nM - > 10 µM. The nature of the 4-substituent present on the pyridine ring was the main factor influencing the inhibitory profile against both isoforms, with 4-halogenophenylpiperazin-1-yl and 3,4,5-trisubstituted-pyrazol-1-yl derivatives showing the most effective inhibition. Some of these sulphonamides were most effective bacterial CA than human (h) CA I and II inhibitors, making them selective for the prokaryotic enzymes. Investigation of bacterial CA inhibitors may be relevant for finding antibiotics with a new mechanism of action compared to the clinically used agents for which substantial drug resistance emerged.

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 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 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.

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.

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 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).

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).

A series of 2-mercapto-substituted-benzenesulfonamides has been prepared by a unique two-step procedure starting from the corresponding 2-chloro-substituted benzenesulfonamides. Compounds bearing an unsubstituted mercapto group and the corresponding S-benzoyl derivatives were investigated as inhibitors of four isoforms of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), i.e., the cytosolic, ubiquitous isozymes CA I and II, as well as the transmembrane, tumor associated isozymes CA IX and XII. These derivatives were medium potency hCA I inhibitors (K(I)s in the range of 1.5-5.7 microM), two derivatives were strong hCA II inhibitors (K(I)s in the range of 15-16 nM), whereas the others showed weak activity. These compounds inhibited hCA IX with inhibition constants in the range 160-1950 nM and hCA XII with inhibition constants in the range 1.2-413 nM. Some of these derivatives showed a certain degree of selectivity for inhibition of the tumor-associated over the cytosolic isoforms, being thus interesting leads for the development of potentially novel applications in the management of hypoxic tumors which overexpress CA IX and XII.

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).

BACKGROUND Sequels of chronic HCV infection are currently one of the most common indications for liver transplantation (LTx). Because HCV reinfection and allograft injury are inevitable, it may influence survival. Earlier studies have not reported higher mortality among HCV-infected patients, but cumulative data seem to contradict these findings. The aim of the study was to analyze post-LTx survival in HCV-positive patients in comparison with non-HCV-positive recipients and impact of antiviral treatment on survival in patients with recurrent HCV hepatitis. MATERIAL AND METHODS Using data from the Polish national transplant registry, a retrospective cohort study of 327 patients who underwent LTx between 2000 and 2012 was performed. Cumulative 5-year mortality for HCV-positive patients vs. HCV-negative recipients and HCV-positive recipients treated with pegylated interferon/ribavirin vs. non-treated subjects was calculated using Kaplan-Meyer methodology. Mortality hazard rates were estimated using univariate proportional Cox models. RESULTS Liver transplantation in HCV-positive vs. HCV-negative recipients was associated with significantly lower survival rate (cumulative 5-year survival 89.8 vs. 80.26%, respectively, p=0.04276) with a 5-year mortality HR of 1.99. Antiviral treatment improved survival irrespective of virological response (84.06% treated vs. 51.22% non-treated, p=0.00003). Univariate Cox HR for HCV treated vs. untreated patients is 0.18. Further improvement of survival was significantly associated with sustained virological response (100% vs. 77.67%, p=0.042). CONCLUSIONS Our study confirms higher mortality risk among HCV-infected transplant recipients, improved survival related to the HCV treatment following graft reinfection, and positive association between the HCV treatment success and better survival.

A new type of constitutionally nonsymmetrical spirans (III), (IV), (VI), which in turn provide access to a series of 3-substituted 1,4,2-benzodithiazine 1,1-dioxide derivatives is synthesized.

Title compounds [(III) and (V)] are synthesized by condensation of sulfonamide (II) with from nitriles (I) in situ generated or directly added carbamidates (IV), respectively.

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.

New compound (Ie) shows high activities against 13 human tumor cell lines representing lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast.

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.

10 Title compounds of type (IX) are prepared and evaluated for their in vitro activities against the full NCI-60 cell line panel.

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.

The pyridine-derived sulfonamides (amines, ethers, hydrazines and sulfides) are investigated as inhibitors of five isoforms of zinc enzyme carbonic anhydrase.

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).

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.

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)

The reaction of 3-amino-2-(2-alkylthio-4-chlorobenzenesulfonyl)guanidines 2a-j with 1,2-dicarbonyl compounds are described. Depending on structure of 1,2-dicarbonyl reagent novel 2-alkylthio-5-chloro-N-(1,2,4-triazin-3-yl)benzenesulfonamides 3-15, 1-(2-alkylthio-4-chlorobenzenesulfonyl)-3-(2-oxobutane-3-ylidenoimino)guanidines 16-18 and 2-alkylthio-4-chloro-N-(1,2-dihydroxycyclobuta[e]1,2,4-triazin-3-yl)benzenesulfonamides 19-21 are obtained. The structures of these compounds were confirmed on the basis of elemental analysis, spectral data and X-ray analysis. The compounds 4, 5, 7, 9, 10, 12-15, 17, 18 and 20 were screened at the National Cancer Institute (NCI) for their in vitro activities against a panel of 56 tumor cell lines and relationship between structure and antitumor activity are discussed. The compounds 10, 12, 17 and 20 were inactive, whereas the other compounds exhibited reasonable activity against one or more human tumor cell lines. The prominent compound 18 showed significant activity against cell lines of colon cancer (HCT-116), renal cancer (786-0) and melanoma (M14) (GI50 in the range 0.33-1.08 microM) as well as good selectivity toward non-small cell lung cancer (HOP-62) cells (GI50 = 0.05 microM, TGI = 0.38 microM and LC50 = 4.83 microM).

The syntheses of new 3-arylideneamino-1-(2-alkythio-4-chloro-5-methylbenzenesul-fonyl)guanidines 2-8 and 1-arylidene-2-(2-alkylthio-4-chloro-5-R 3 -benzenesulfonyl)-3-methylaminoguanidines 9-16 are described. The in vitro antitumor screening of compounds 2, 3, 9 and 10 was evaluated at the Institute of Pharmacy, University of Greifswald. The remaining compounds 5, 11-14 and 16 were screened at the National Cancer Institute (NCI) for their activities against a panel of 55 human tumor cell lines, and relationships between structure and anticancer activity in vitro are discussed. The highest anticancer activity was found for 2-(2-benzylthio-4-chloro-5-methylbenze-nesulfonyl)-3-methylamino-1-(5-nitrothienylidene)guanidine (12) (GI 5 0 in the range 0.3-0.6 μM), while other compounds exhibit reasonable (16) or moderate (9, 13) anticancer activities.

A series of N-substituted N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)guanidine derivatives bearing sulfonamide moiety have been screened in vitro for antibacterial activity against isolates from patients with infections of oral cavity, respiratory tract and intestinal tract. The majority of compounds exhibited good antibacterial potency. 1-[4-Chloro-5-methyl-2-(4-trifluoromethylbenzylthio)benzenesulfonyl]-3-(3-sulfamoylphenyl)guanidine (13) showed very strong activity, with MIC ≤ 6.2 μg/ml against eleven bacteria strains belonged to Gram-positive anaerobes and aerobes. Furthermore, compound 13 exhibited promising activity toward highly resistant microorganisms such as methicillin-resistant Staphylococcus aureus and Enterococcus faecalis. It was found that Parvimonas micra, Finegoldia magna, Peptostreptococcus anaerobius, Propionibacterium acnes showed the highest susceptibility toward the investigated guanidines.