Synthesis of 1,2,4-triazole derivatives: binding properties on endothelin receptors

In the present study we describe the synthesis of a new series of 1,2,4-triazoles: [3-(arylmethyl)thio-5-aryl-4H-[1,2,4]triazol-4-yl]acetic acids 5a-g, [5-(arylmethyl)thio-3-aryl-1H-[1,2,4]triazol-1-yl]acetic acids 8a-d, and [3-(aryl-methyl)thio-5-aryl-1H-[1,2,4]triazol-1-yl] acetic acids 9a-d. These compounds were tested in binding assays to evaluate their ability as ligands for human ET(A) and ET(B) receptors stably expressed in CHO cells; some of the tested compounds showed affinity in the micromolar range.     

Inhibition of human topoisomerase I and activation of caspase-3 by aza-angucyclinones and arylaminopyrimido[4,5-c]isoquinoline-7,10-quinones

Cancer is the second cause of death in the world after cardiovascular diseases. Cancer cells acquire capacities not present in normal cells, such as self-sufficiency, resistance to antiproliferative stimuli, evasion of apoptosis, unlimited replication, invasiveness and metastasis. Consequently, it is of major interest to explore and develop molecules with anticancer activity directed to specific targets. In this study, we aimed to evaluate two series of polycyclic quinones: aza-angucyclinone and arylaminopyrimido[4,5-c]isoquinoline-7,10-quinones, in their capacity to inhibit human topoisomerase I (TOP1) and to trigger apoptosis through activation of caspase-3. We evaluated the capacity of the two series of polycyclic quinones to inhibit TOP1, using a DNA supercoiled relaxation assay and their capacity to induce apoptosis through the activation of caspase-3 in HL60 cells. Both series of quinones inhibited TOP1 activity over 50%. When we evaluated the pro-apoptotic capacity of both series of quinones, at therapeutically relevant concentrations, the arylaminoquinones ADPA-1CC (methyl 7-(4-methoxyphenyl)amino-1,3-dimethyl-5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylate), P4 (9-phenylamino-3,4-dihydrophenanthridine-1,7,10(2H)-trione) and the aza-angucyclinone OH-6H (8-hydroxy-2,4-dimethyl-2H,4H-benzo[g]pyrimido[4,5-c]isoquinoline-1,3,7,12-tetraone) increased the caspase-3 activity by approximately 2-fold over the control. The series of the arylaminoquinones and aza-angucyclinones showed differential antiproliferative capacity. We further identified a group of them that showed antiproliferative capacity possibly through inhibition of TOP1 and by activation of caspase-3. This group of molecules may represent a potential pharmacological tool in the treatment against cancer.     

Synthesis and biological evaluation of 2-aroyl-4-phenyl-5-hydroxybenzofurans as a new class of antitubulin agents

Microtubules are among the most successful targets for development of compounds useful for anticancer therapy. Continuing our project to develop new small molecule antitumor agents, two new series of derivatives based on the 2-aroyl-4-phenylbenzofuran molecular skeleton were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization and cell cycle effects. SAR were elucidated with various substitutions on the benzoyl moiety at the 2-position of the benzofuran ring. The most promising compound in this series, the (5-hydroxy-4-phenylbenzofuran-2-yl)(4-methoxyphenyl)methanone derivative (3d), has significant growth inhibitory activity in the submicromolar range against the Molt4, CEM and HeLa cancer cell lines and interacts with tubulin by binding to the colchicine site. Exposure to 3d led to the arrest of K562 cells in the G2-M phase of the cell cycle and to the induction of apoptosis.     

Synthesis and anti-picornaviridae in vitro activity of a new class of helicase inhibitors the N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl] alkyldicarboxamides

A series N,N'-bis[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkyldicarboxamides (3a-f and 5a-j) were prepared starting from their already known (1a-d) and (4a-c) or new (4d) amine parents. Because of the antiviral activity of several N-[4-(1H(2H)-benzotriazol-1(2)-yl)phenyl]alkylcarboxamides previously reported, title compounds were evaluated in vitro for cytotoxicity and antiviral activity against viruses representative of Picornaviridae, [i.e. Enterovirus Coxsackie B2 (CVB-2) and Polio (Sb-1)] and of two of the three genera of the Flaviviridae [Bovine Viral Diarrhea Virus (BVDV) and Yellow Fever Virus (YFV)]. Furthermore, because of the in silico activity against the RNA-dependent RNA-helicase of Polio 1 previously reported, title compounds were evaluated against the 3D model of the Sb-1 helicase and against the 2D model of the CVB-2 helicase. As a reference we used the antiviral and in silico activities of an imidazo counterpart of the title compounds, N,N'-bis[4-(2-benzimidazolyl)phenyl]alkyldicarboxamides (III) that other authors reported to be able to inhibit the corresponding enzyme of Hepatitis C Virus (HCV). In cell-based antiviral assays, N,N'-bis[4-(1H-benzotriazol-1-yl)phenyl]alkyldicarboxamides (3a-f) resulted completely inactive whereas the bis-5,6-dimethyl-benzotriazol-2-yl derivatives (5d-f) exhibited good activity against the Enteroviruses, (EC(50)s ranged between 7 and 11 microM against CVB-2 and 19-52 against Sb-1). Interestingly, bis-5,6-dichloro-benzotriazol-2-yl derivatives (5h-j) showed very selective activity against CVB-2 (EC(50)s = 4-11 microM) whereas they resulted completely inactive against all the other viruses screened. In general, all title compounds showed a good cytotoxicity profile in MT-4 cells. Molecular modeling investigations showed that active compounds may interact with the binding site of the Sb-1 helicase and that their free binding energy values are in agreement with their EC(50)s values.     

Syntheses and properties of selected derivatives of pyrimido[5,4-e]-1,3-thiazine and pyrimido[4,5-d]pyrimidine

In the reactions of ethyl 4-chloro/tosyloxy/-2-methylpyrimidine-5-carboxylate with differently substituted thioureas, new derivatives of 2,3-dihydro-7-methylpyrimido-[5,4-e]-1,3-thiazine (5-9) and of 7-methyl-1,2,3,4-tetrahydropyrimido[4,5-d]pyrimidine (12, 13) were obtained. Besides, some derivatives of 4-phenylamino-2-methylpyrimidine-5-carboxylic acid (15-20) were also synthesized. Structure of the compounds was confirmed by spectral analysis (IR, H-NMR) and chemical transformations. In the screening pharmacological examinations some of the compounds revealed analgesic, antiinflammatory and immunosuppressive activity.     

Synthesis and anticonvulsant activity of 7-alkoxy-triazolo-[3, 4-b]benzo[d]thiazoles

The present study describes the chemical synthesis and anticonvulsant activity evaluation of a series of 7-alkoxy-triazolo-[3, 4-b]benzo[d]thiazoles. Most compounds exhibited good anticonvulsant activity in the Maximal electroshock (MES) test. And the structure-activity relationships (SAR) were analyzed. Among the compounds studied, 7-octyloxy-triazolo-[3, 4-b]benzo[d]thiazole (5g) was found to be the most potent compound with a median effective dose (ED(50)) value of 8.0 mg/kg and a protective index (PI) value of 15.0, possessing better anticonvulsant activity and higher safety than marketed drugs carbamazepine and phenytoin. The mechanism study of compound 5g showed that it displayed broad spectrum activity in several models, and it is likely to have several mechanisms of action (including inhibiting voltage-gated ion channels and GABAergic activity).     

Synthesis, antimycobacterial activities and phototoxic evaluation of 5H-thiazolo[3,2-a]quinoline-4-carboxylic acid derivatives

Thirty four novel 7-fluoro/nitro-1,2-dihydro-5-oxo-8-(sub)-5H-thiazolo[3,2-a]quinoline-4-carboxylic acids were synthesized from 2,4-dichlorobenzoic acid and 2,4-dichloro-5-fluoroacetophenone by multi step reaction, evaluated for in vitro and in vivo antimycobacterial activities against Mycobacterium tuberculosis H37Rv (MTB), multi-drug resistant Mycobacterium tuberculosis (MDR-TB) and Mycobacterium smegmatis (MC2) and also tested for the ability to inhibit the supercoiling activity of DNA gyrase from M. smegmatis. Among the synthesized compounds, 8-[6-[[(1,1-dimethylethoxy)carbonyl]amino]-3-azabicyclo[3.1.0]hex-3-yl]-1,2-dihydro-7-nitro-5-oxo-5H-thiazolo[3,2-a]quinoline-4-carboxylic acid (10q) was found to be the most active compound in vitro with MIC of 0.08 microM and <0.08 microM against MTB and MDR-TB respectively. Compound 10q was found to be 4.5 and >570 times more potent than isoniazid against MTB and MDR-TB respectively. In the in vivo animal model 10q decreased the bacterial load in lung and spleen tissues with 2.51 and 3.71-log10 protections respectively at the dose of 50 mg/kg body weight.     

Liquid-crystalline polymers containing heterocycloalkanediyl groups as mesogens, 6. Liquid-crystalline poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl methacrylate] and poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl acrylate]

The synthesis and characterization of poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl methacrylate] and poly[trans-11-{4-[5-(4-methoxyphenyl)-1,3-dioxan-2-yl]-2,6-dimethylphenoxy}undecyl acrylate] is presented. Both polymers exhibit nematic mesophases and do not present side-chain crystallization. At temperatures higher than 160°C the 1,3-dioxane-2,5-diyl groups undergo a thermally induced trans-cis isomerization. A radical mechanism is proposed for this isomerization.     

Combretastatin-chalcone hybrids: synthesis and cytotoxicity

A series of all-trans-1-aryl-4-aryl-5-aryl-2,4-pentanediene-1-one (3), a hybridized form of chalcone and combretastatin, was synthesized and evaluated against a panel of cancer cell lines, including B16, murine melanoma; HCT116, colon cancer; A431, human epidermoid carcinoma; and human umbilical venous endothelial cells (HUVEC). Structure-activity relationships analysis of this series revealed that a 2,5-dihydroxyphenyl at position 1 of the 2,4-pentanediene-1-one was essential for cytotoxicity. all-trans-1-(2,5-Dihydroxyphenyl)-5-(4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-2,4-pentanediene-1-one (3a) was the most potent compound from this series.     

Rapid and highly sensitive method for the determination of verapamil, [2H7]verapamil and metabolites in biological fluids by liquid chromatography-mass spectrometry

A rapid and highly sensitive method for the determination of verapamil [2,8-bis-(3,4-dimethoxyphenyl)-6-methyl-2-isopropyl-6-azaoctanitrile+ ++] and [2H7]verapamil and their primary metabolites D-617 [2-(3,4-dimethoxyphenyl)-5-methylamino-2-isopropylvaleronitrile], D-703 [2-(4-hydroxy-3-methoxyphenyl)-8-(3,4-dimethoxy-phenyl)-6-methyl-2-iso-p ropyl-6-azaoctanitrile], D-702 [2-(3,4-dimethoxy-phenyl)-8-(4-hydroxy-3-methoxyphenyl)-6-methyl-2-isopr opyl-6-azaoctanitrile], norverapamil [2,8-bis-(3,4-dimethoxyphenyl)-2-isopropyl-6-azaoctanitrile] and secondary metabolites D-620 [2-(3,4-dimethoxyphenyl)-5-amino-2-isopropylvaleronitrile], D-717 [2-(4-hydroxy-3-methoxyphenyl)-5-amino-2-isopropylvaleronitrile], and D-715 [2-(4-hydroxy-3-methoxyphenyl)-8-(3,4-dimethoxy-phenyl)-2-isopropyl-6-++ +azaoctanitrile] has been developed using high-performance liquid chromatography-electrospray mass spectrometry. D-832, the gallopamil analogue of D-617 and [2H3]norverapamil were used as internal standards. The analytes were extracted automatically from plasma and intestinal perfusate using end-capped CN- and C2 solid-phase extraction cartridges. Separation of the eight analytes was achieved on a LUNA C8 analytical column (150x2 mm I.D., 5 microm particle size) with 5 mM ammonium acetate-acetonitrile as the mobile phase run with a gradient from 70:30 to 40:60 and run times of 15 min. With the mass spectrometer operated in the selected-ion monitoring mode, the limits of quantification in plasma and intestinal perfusate were 1 pmol/ml for D-620, D-617, D-702, D-703, norverapamil, verapamil, and [2H7]verapamil and 2.5 pmol/ml for D-717 and D-715 using a sample size of 1 ml plasma and intestinal perfusate. The method described was successfully applied to the determination of verapamil, [2H7]verapamil and their metabolites in human plasma and intestinal fluid in pharmacokinetic studies.     

Studies on two new mixed ligand platinum compounds with a trans-geometry

In this paper we report the synthesis and in vitro activity of two new mixed ligand platinum complexes: trans-[PtCl?(thiazole)(imidazole) [JH3] and trans-[PtCl?(thiazole)(3-hydroxypyridine) [JH4]. Although the compounds are less active than cisplatin against the parent ovarian cancer cell line A2780, they are more active than cisplatin against the resistant cell lines A2780(cisR) and A2780(ZD0473R), thus indicating that JH3 and JH4 have been better able to overcome mechanisms of resistance operating in A2780(cisR) and A2780(ZD0473R). When Pt-DNA binding levels at 24 h in A2780, A2780(cisR) and A2780(ZD0473R) cell lines are compared it is found that whereas for cisplatin the values in resistant cell lines are significantly lower than that in the parent cell line, for JH3 and JH4 Pt-DNA binding levels in the parent and resistant cell lines are comparable, thus providing an explanation for variations in activity of the compounds in the three cell lines.     

Preparation of 4-tert-butyloxocalix[n]arenes and their properties as UV-absorbers

5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetrahydroxy-2-oxocalix[4]arene ( 4a ), 5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40,41,42-hexahydroxy-2-oxocalix[6]arene ( 4b ), and octa-tert-butyl-octahydroxy-trioxocalix[8]arene ( 4c ) were synthesized via 4-tert-butylcalix[4]-, [6]- and [8]arenes from 4-tert-butylphenol as a starting material. 5,5′-Di-tert-butyl-2,2′-dihydroxybenzophenone ( 7 ) was synthesized via 5,5′-di-tert-butyl-2,2′-dimethoxybenzophenone ( 6 ) from bis(5-tert-butyl-2-methoxyphenyl)methane ( 5 ). 1,4-Dioxane solutions of 4a , 4b , 4c , 6 , and 7 were irradiated. The photostabilities of 4b and 4c were found to be better than those of 4a , 6 , and 7 . A poly(vinyl chloride) film, containing 0,06 mmol/g of 4b , was found to be most stable against photoxidation.     

Synthesis and biological evaluation of a series of 2-(substitutedphenyl)benzothiazoles

A series of 2-phenylbenzothiazoles has been synthesized either by i) condensation of different aromatic aldehydes with 2-aminothiophenol or ii) condensation of N-(2-chlorophenyl)benzothioamides in KOH catalyzed by potassium fericyanide. The structures of synthesized compounds were confirmed by IR, MS, and (1)H-NMR. The results of biological activity screening showed that six compounds including 2-phenylbenzothiazol (1a), 2-(2-chlorophenyl)benzothiazole (1b), 2-(3-chlorophenyl)benzothiazole (1c), 2-(4-hydroxyphenyl)benzothiazole (1e), 2-(4-dimethylaminophenyl)benzothiazole (1h) and 2-(2,3,4-trimethoxyphenyl)benzothiazole (1i) exhibited significant antibacterial activities; two compounds (1a, 1e) exhibited antifungal activities. Especially, 1e showed considerable antimicrobial activity against both A. niger and F. oxysporum. The brominated derivative of 1e displayed extended spectrum against all four bacterial strains tested with lower MIC values. In vitro cytotoxicity of the synthesized compounds was evaluated on three cancer cell lines (A549, HT1080, MCF7-MDR). The results indicated that three compounds (1e, 1g, 1i) exhibited significant cytotoxic activity on A549 and MCF7-ADR cells (IC(50), 10.07-13.21 μg/ml). Brominated and nitrated derivatives (1k, 1l, respectively) of 1e exhibited even more potent cytotoxicity.     

A new microtubule-targeting compound PBOX-15 inhibits T-cell migration via post-translational modifications of tubulin

The ordered, directional migration of T-lymphocytes is a key process during immune surveillance, immune response, and development. A novel series of pyrrolo-1,5-benzoxazepines have been shown to potently induce apoptosis in variety of human chemotherapy resistant cancer cell lines, indicating their potential in the treatment of both solid tumors and tumors derived from the hemopoietic system. Pyrrolobenzoxazepine 4-acetoxy-5-(1-naphtyl)naphtho[2,3-b]pyrrolo[1,2-d][1,4]-oxazepine (PBOX-15) has been shown to depolymerize tubulin in vitro and in the MCF7 breast cancer cell line. We hypothesized that this may suggest a role for this compound in modulating integrin-induced T-cell migration, which is largely dependent on the microtubule dynamics. Experiments were performed using human T lymphoma cell line Hut78 and peripheral blood T-lymphocytes isolated from healthy donors. We observed that human T-lymphocytes exposed to PBOX-15 have severely impaired ability to polarize and migrate in response to the triggering stimulus generated via cross-linking of integrin lymphocyte function associated antigen-1 receptor. Here, we show that PBOX-15 can dramatically impair microtubule network via destabilization of tubulin resulting in complete loss of the motile phenotype of T-cells. We demonstrate that PBOX-15 inhibitory mechanisms involve decreased tubulin polymerization and its post-translational modifications. Novel microtubule-targeting effects of PBOX-15 can possibly open new horizons in the treatment of overactive inflammatory conditions as well as cancer and cancer metastatic spreading.     

Novel (S)-(-)- and R-(+)-seco-iso-cyclopropylfurano[e]indoline-5,6,7-trimethoxyindole-2-carboxamide (iso-CFI) analogs of duocarmycin C2: synthesis and biological evaluation

Racemic seco-iso-CFI (cyclopropylfurano[e]indoline) analogs of the duocarmycins and CC-1065 have recently been reported by our group. These compounds covalently react with AT-rich sequences of DNA, and they exhibit potent cytotoxicity against cancer cells but are less toxic to normal bone marrow cells. This article details the synthesis of enantiomerically pure (S)-(-)- and R-(+)-seco-iso-CFI (cyclopropylfurano[e]indoline)-5,6,7-trimethoxyindole-2-carboxamide analogs, (S)-(-)-1 and (R)-(+)-1, respectively. The covalent DNA binding properties and cytotoxicity of both enantiomers against L1210 murine leukemia and B16 murine melanoma cells grown in culture are reported and compared to racemate (+/-)-1. The natural (S)-(-)-enantiomer of 1 is more reactive with DNA and more cytotoxic than its unnatural mirror image and the racemic mixture.     

Synthesis and characterization of lithium and magnesium complexes based on [EDTA][PEG400]2 and [EDTA]3[PEG400]7

Two distinct types of host polymers, [EDTA]₃‐[PEG400]₇ and [EDTA][PEG400]₂, consisting of polyether chains linked together by ethylenediaminetetraacetic acid (EDTA) chelating units, were synthesized from EDTA acetate esters and poly(ethylene glycol) 400 (PEG400). Their structures were revealed by analytical analyses, viscosimetric measurements, NMR and FT‐IR studies. Direct dissolution of δ‐LiCl and δ‐MgCl₂ in these prepared host polymers resulted in the following complexes: [EDTA]₃‐[PEG400]₇/(LiCl)_6.39, [EDTA]₃[PEG400]₇/(MgCl₂)_8.23, [EDTA]₃[PEG400]₇/(LiCl)_6.39(MgCl₂)_6.16, [EDTA][PEG400]₂/ (LiCl)_2.26, [EDTA][PEG400]₂/(MgCl₂)_1.98 and [EDTA]‐[PEG400]₂/(LiCl)_2.26(MgCl₂)_1.98. Mid‐ and far‐FT‐IR spectroscopic studies revealed the following properties for all six complexes: a) the polyether chains are in the trans–gauche–trans conformation; b) the Mg²⁺ ion could be hexa‐ or heptacoordinated to the chelating sites of EDTA; c) the Li⁺ ion is preferentially coordinated by the oxygen atoms of the residual acetate groups and polyether moieties. Results of conductivity measurements at room temperature indicated that the proposed Mg products might be very useful for the development of electrochemical transducers for measuring water hardness.

Esterification of EDTA dianhydride with PEG400; (2): Synthesis of the complexes (MX_n = LiCl/MgCl₂).     

8-(Heteroaryl)phenalkyl-1-phenyl-1,3,8-triazaspiro[4.5]decan-4-ones as opioid receptor modulators

A series of N-biarylalkyl-1-phenyl-1,3,8-triazaspiro[4.5]decan-4-ones were prepared and evaluated for biological activity at opioid (mu, delta, kappa) and opioid receptor like-1 (ORL-1) G-protein coupled receptors. Substitution on the biaryl moiety produced enhanced affinity for the mu-opioid receptor.     

Design and synthesis of 2-methylthio-3-substituted-5,6-dimethylthieno [2,3-d] pyrimidin-4(3H)-ones as analgesic, anti-inflammatory and antibacterial agents

Pain and inflammation are simultaneous responses in bacterial infections. In current clinical practice, two groups of agents like antibacterial and non-steroidal anti-inflammatory drugs (NSAID's) are prescribed simultaneously. Regrettably, none of the drug possesses these activities in a single component. Exploiting the bioisosterism concept, we have documented that 2-phenyl-3-substituted quinazolines, 2,3-disubstituted quinazolines, 2-methyl-3-substituted quinazolin-4-(3H)-ones and 2-methylthio-3-substituted quinazolin-4-(3H)-ones exhibited good analgesic and anti-inflammatory activities. The present work is an extension of our ongoing efforts towards the development and identification of lead molecules by bioisostere concept, for which we designed some of 2-methylthio-3-substituted-5,6-dimethylthieno[2,3-d] pyrimidin-4(3H)-ones. The title compounds were investigated for analgesic, anti-inflammatory and antibacterial activities. While the test compounds exhibited significant activity, the compounds (6-9) showed more potent analgesic activity, and the compounds (8, 9) showed anti-inflammatory activity comparable to the reference standard diclofenac.     

Towards metabolically stable 5-HT7 receptor ligands: a study on 1-arylpiperazine derivatives and related isosters

Serotonin 7 (5-hydroxytryptamine7 or 5-HT₇) is the most recently identified serotonin receptor. It is involved in mood disorders and is studied as a target for antidepressants. Here, we report on the structural manipulation of the 5-HT₇ receptor ligand 4-[2-(3-methoxyphenyl)ethyl]-1-(2-methoxyphenyl)piperazine (1a) aimed at obtaining 5-HT₇ receptor ligands endowed with good in vitro metabolic stability. A set of N-[3-methoxyphenyl)ethyl-substituted] 1-arylpiperazine, 4-arylpiperidine and 1-aryl-4-aminopiperidine was synthesized and tested in radioligand binding assays at human cloned 5-HT₇ and 5-HT_1A receptors. In vitro metabolic stability of the target compounds was assessed after incubation with rat hepatic S9 microsomal fraction. Among the new compounds, 1-(2-biphenyl)-4-[2-(3-methoxyphenyl)ethyl]piperazine (1d) and 4-(2-biphenyl)-1-[2-(3-methoxyphenyl)ethyl]piperidine (2d) showed a good compromise between affinity at 5-HT₇ receptor (K _i = 7.5 nM and 13 nM, respectively) and in vitro metabolic stability (26 and 65 % recovery of parent compound, respectively) but were poorly selective over 5-HT_1A receptor.