Synthesis and positive inotropic activity of N-(4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(piperazin-1-yl)acetamide derivatives

A series of N-(4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(piperazin-1-yl)acetamide derivatives were synthesized and their positive inotropic activity was evaluated by measuring left atrium stroke volume on isolated rabbit heart preparations. Several compounds showed favorable activity compared with the standard drug, milrinone, among which N-(1-benzyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)-2-(4-benzylpiperazin-1-yl)acetamide 6j was found to be the most potent with the 13.2% increased stroke volume (milrinone 4.7%) at concentration of 3x10(-5) M in our in vitro study. The chronotropic effects of those compounds having inotropic effects were also evaluated in this work.     

Design and Synthesis of 1-Substituted-4-(4-Nitrophenyl)-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones as a New Class of Antihistaminic Agents

Russian Journal of Bioorganic Chemistry - Some new 1-substituted-4-(4-nitrophenyl)-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones were synthesized and screened for their H1-antihistaminic activity....     

Synthesis and anticonvulsant activity of 7-alkoxyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinolines

A series of 7-alkoxyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline derivatives was synthesized using 6-hydroxy-3,4-dihydro-1H-quinolin-2-one as a starting material. Their anticonvulsant activities were evaluated by the maximal electroshock test (MES test) and the subcutaneous (s.c.) pentylenetetrazol test (scMet test), and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). MES and scMet tests show that 7-(4-fluorobenzyloxy)-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline 4l was found to be the most potent with ED50 value of 11.8 and 6.7 mg kg(-1) and protective index (PI = TD50/ED50) value of 4.6 and 8.1, respectively.     

Synthesis and positive inotropic evaluation of N-(1-oxo-1,2,4,5-tetrahydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)acetamides bearing piperazine and 1,4-diazepane moieties

Two series of N-(1-oxo-1,2,4,5-tetrahydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)acetamides bearing piperazine and 1,4-diazepane moieties were synthesized and screened for their positive inotropic activity by measuring left atrium stroke volume on isolated rabbit heart preparations. Most of the derivatives exhibited better in vitro positive inotropic activity than the existing drug, milrinone, among which 2-(4-(4-chlorobenzyl)-1,4-diazepan-1-yl)-N-(1-oxo-1,2,4,5-tetrahydro-[1,2,4]triazolo[4,3-a]quinolin-7-yl)acetamide 6c proved to be the most potent with 15.48 ± 0.27% increased stroke volume (milrinone: 2.46 ± 0.07%) at a concentration of 3 × 10(-5) M. The chronotropic effects of the compounds that exhibited inotropic effects were also evaluated.     

Synthesis and pharmacological investigation of novel 4-benzyl-1-substituted-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-ones as new class of H1-antihistaminic agents

A series of novel 1-substituted-4-benzyl-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-ones were synthesized by the cyclization of 2-hydrazino-3-benzyl-3H-quinazolin-4-one with various one-carbon donors. The starting material 2-hydrazino-3-benzyl-3H-quinazolin-4-one was synthesized from benzylamine by a new innovative route. When tested for their in vivo H1 -antihistaminic activity on guinea pigs, all the test compounds protected the animals from histamine induced bronchospasm significantly. The compound 1-methyl-4-benzyl-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-one (II) emerged as the most active compound of the series and it is more potent (percent protection 76%) when compared to the reference standard chlorpheniramine maleate (percent protection 71%). Compound II showed negligible sedation (7%) when compared to chlorpheniramine maleate (30%). Hence it could serve as prototype molecule for further development as a new class of H1 -antihistamines.     

Synthesis and biological evaluation of 1-substituted-3-(6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)pyrazoles as transforming growth factor-β type 1 receptor kinase inhibitors

A series of 1-substituted-3-(6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)pyrazoles 14a-ae, 16a, 16b, and 21a-c has been prepared and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. The 4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-N-(4-methoxyphenyl)-3-(6-methylpyridin-2-yl)-1H-pyrazole-1-carbothioamide (14n) inhibited ALK5 phosphorylation with IC(50) value of 0.57 nM and showed 94% inhibition at 100 nM in a luciferase reporter assay using HaCaT cells permanently transfected with p3TP-luc reporter construct.     

Synthesis and structure elucidation of novel fused 1,2,4-triazine derivatives as potent inhibitors targeting CYP1A1 activity

Synthesis and structure elucidation of new series of novel fused 1,2,4-triazine derivatives 3a-3f, 4a-4i and 6a-6b and their inhibitory activities are presented. Molecular structures of the synthesized compounds were confirmed by (1)H NMR, (13)C NMR, MS spectra and elemental analyses. X-ray crystallographic analysis was performed on 2-acetyl-8-(N,N-diacetylamino)-6-(4-methoxybenzyl)-3-(4-methoxy-phenyl)-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 3d and 2-acetyl-8-(N-acetylamino)-6-benzyl-3-(4-chlorophenyl)-3-methyl-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 4e to secure their structures. The inhibitory effect of these compounds toward the CPY1A1 activity was screened to determine their potential as promising anticancer drugs. Our data showed that compounds 4e, 5a, 5b and 6b possess the highest inhibitory effects among all tested compounds. Furthermore, analysis of triazolotriazine derivatives docking showed that these compounds bind only at the interface of substrate recognition site 2 (SRS2) and (SRS6) at the outer surface of the protein. Amino-acids ASN214, SER216 and ILE462 participate in the binding of these compounds through H-bonds.     

The effect of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline on cell growth, cell cycle, induction of DNA fragmentation, and activity of caspase 3 in murine leukemia L1210 cells and fibroblast NIH-3T3 cells

Quinazolines are multitarget agents, which have broad spectrum of biological activity, and some of them are now in cancer clinical testing. 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline is a new synthetically prepared derivative, which in our previous study showed cytotoxic effects on cancer cell lines HeLa and B16. Quinazoline, at micromolar concentrations, induced morphological changes and necrosis of B16 cells, and at nanomolar concentrations it produced changes of F-actin cytoskeleton. It did not cause changes in the cell cycle, did not induce apoptotic cell death in B16 cells, did not have a mutagenic effect, and did not even behave as a typical intercalating agent. Little significant reduction of tumor volume in intramuscular transplanted B16 cells was observed. The aim of the present study was to examine the cytotoxic effect of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline on murine leukemia L1210 cells and fibroblast NIH-3T3 cells. Induction of cell morphology and cell cycle changes, induction of apoptosis and caspase 3 activity were studied. Quinazoline acted cytotoxically on both cell lines. The sensitivity of leukemia L1210 cells to the quinazoline was higher than that of fibroblast NIH-3T3. The IC(100) was 12 microM for L1210 cells and 24 microM for NIH-3T3 cells. No effect of quinazoline on the cell cycle profile of L1210 and NIH-3T3 was detected, however, quinazoline induced an increase of the sub-G(0) cell fraction, apoptotic DNA fragmentation, and apoptotic morphological changes at a concentration of 12 microM. This quinazoline concentration induced caspase 3 activity. Our results demonstrated that induction of apoptotic cell death via activation of caspase 3 contributed to the cytotoxic effects of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline in murine leukemia L1210 cells.     

2-aryl-8-chloro-1,2,4-triazolo[1,5-a]quinoxalin-4-amines as highly potent A1 and A3 adenosine receptor antagonists

Some 2-aryl-8-chloro-1,2,4-triazolo[1,5-a]quinoxaline derivatives 2-18, obtained by introducing different substituents on either the 4-amino moiety (acyl or carbamoyl groups) or the 2-phenyl ring (4-OCH3) of previously reported 8-chloro-2-phenyl-1,2,4-triazolo[1,5-a]quinoxalin-4-amine (1), have been synthesized and tested in radioligand binding assays at bovine A1 and A(2A) and at cloned human A1 and A3 adenosine receptors. The rationally designed 8-chloro-2-(4-methoxy-phenyl)-1,2,4-triazolo[1,5-a]quinoxalin-4-acetylamine (14) can be considered one of the most potent and hA3 versus hA1 selective AR antagonists reported till now. The structure-activity relationships of compounds 2-18 are in agreement with those of previously reported 2-aryl-1,2,4-triazolo[4,3-a]quinoxalines (series A) and 2-arylpyrazolo[3,4-c]quinolines (series B), thus suggesting a similar AR binding mode. In fact, the importance for the A3 receptor-ligand interaction of both a strong acidic NH proton donor and a C=O proton acceptor at position-4, able to engage hydrogen-bonding interactions with specific sites on the A3 AR, has been confirmed. Using our recently published hA3 receptor model, to better elucidate our experimental results, we decided to theoretically depict the putative TM binding motif of the herein reported 1,2,4-triazolo[1,5-a]quinoxaline derivatives on human A3 receptor. Structure-activity relationships have been explained analyzing the three-dimensional structure of the antagonist-receptor models obtained by molecular docking simulation.     

Synthesis and anticonvulsant evaluation of 4-(4-alkoxylphenyl)-3-ethyl-4H-1,2,4-triazoles as open-chain analogues of 7-alkoxyl-4,5-dihydro[1,2,4]triazolo[4,3-a]quinolines

A series of 4-(4-alkoxylphenyl)-3-ethyl-4H-1,2,4-triazole derivatives was synthesized as open-chain analogues of 7-alkoxyl-4,5-dihydro[1,2,4]triazolo[4,3-a]quinolines. Their anticonvulsant activities were evaluated by the maximal electroshock test (MES test) and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). MES test showed that 3-ethyl-4-(4-octyloxyphenyl)-4H-1,2,4-triazole 3q was found to be the most potent with ED(50) value of 8.3mg/kg and protective index (PI=TD(50)/ED(50)) value of 5.5, but compound 3r, 3-ethyl-4-(4-octyloxyphenyl)-4H-1,2,4-triazole, exhibited better PI value of 9.3, which was much greater than PI value of the prototype drug phenytoin. For explanation of the possible mechanism of action, the compound 3r was tested in pentylenetetrazole test, isoniazid test, thiosemicarbazide test, 3-mercaptopropionic acid and strychnine test.     

Exploration and optimization of substituted triazolothiadiazines and triazolopyridazines as PDE4 inhibitors

An expansion of structure–activity studies on a series of substituted 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine PDE4 inhibitors and the introduction of a related [1,2,4]triazolo[4,3-b]pyridazine based inhibitor of PDE4 is presented. The development of SAR included strategic incorporation of known substituents on the critical catachol diether moiety of the 6-phenyl appendage on each heterocyclic core. From these studies, (R)-3-(2,5-dimethoxyphenyl)-6-(4-methoxy-3-(tetrahydrofuran-3-yloxy)phenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine (10) and (R)-3-(2,5-dimethoxyphenyl)-6-(4-methoxy-3-(tetrahydrofuran-3-yloxy)phenyl)-[1,2,4]triazolo[4,3-b]pyridazine (18) were identified as highly potent PDE4A inhibitors. Each of these analogues was submitted across a panel of 21 PDE family members and was shown to be highly selective for PDE4 isoforms (PDE4A, PDE4B, PDE4C, PDE4D). Both 10 and 18 were then evaluated in divergent cell-based assays to assess their relevant use as probes of PDE4 activity. Finally, docking studies with selective ligands (including 10 and 18) were undertaken to better understand this chemotypes ability to bind and inhibit PDE4 selectively.     

Comparison of inhibitory activity of isomeric triazolopyridine derivatives towards adenosine receptor subtypes or do similar structures reveal similar bioactivities?

The synthesis of an array of 8-amino-2-aryl-[1,2,4]triazolo[1,5-a]pyridine-6-carboxyl amide derivatives is described for the first time. A subset of 20 derivatives were compared to their isomeric 5-amino-2-aryl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxyl amide counterparts with regard to their potential to inhibit the human adenosine 2a (hA2a) receptor and their selectivity against the human adenosine 1 (hA1) receptor. Based on the analysis of H-bond donor/acceptor capabilities of the isomeric triazolopyridine pairs it can be concluded that the H-bond donor strength of the free amino functionality is the main determinant for hA2a inhibitory activity and hA1 selectivity.     

Antimicrobial activity of some substituted triazoloquinazolines

Fifteen substituted 1,2,4-triazolo[4,3-c]quinazolines were tested for antibacterial and antifungal effects. The most effective derivatives had the triazoloquinazoline skeleton substituted with the pharmacologically active chromophores--morpholine, chlorine and nitro group. The broadest antimicrobial activity was found with 5-morpholin-4-yl-3-(5-nitrothien-2-yl)[1,2,4]triazolo[4,3-c]quinazoline in concentration of 10 mg/L for B. subtilis, 50 mg/L for S. aureus and 100 mg/L for C. tropicalis. The highest tested concentration of derivative caused 83% growth inhibition of R. nigricans.     

Discovery of AZD3514, a small-molecule androgen receptor downregulator for treatment of advanced prostate cancer

Removal of the basic piperazine nitrogen atom, introduction of a solubilising end group and partial reduction of the triazolopyridazine moiety in the previously-described lead androgen receptor downregulator 6-[4-(4-cyanobenzyl)piperazin-1-yl]-3-(trifluoromethyl)[1,2,4]triazolo[4,3-b]pyridazine (1) addressed hERG and physical property issues, and led to clinical candidate 6-(4-{4-[2-(4-acetylpiperazin-1-yl)ethoxy]phenyl}piperidin-1-yl)-3-(trifluoromethyl)-7,8-dihydro[1,2,4]triazolo[4,3-b]pyridazine (12), designated AZD3514, that is being evaluated in a Phase I clinical trial in patients with castrate-resistant prostate cancer.     

Anticonvulsant and toxicity evaluation of some 7-alkoxy-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline-1(2H)-ones

To further investigate anticonvulsant activity of quinoline derivatives, a series of 7-alkoxy-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline-1(2H)-one derivatives was synthesized starting from 7-hydroxyl-3,4-dihydro-2(1H)-quinoline. In initial (phase I) screening and quantitative (phase II) evaluation, compound 7-benzyloxyl-4,5-dihydro-[1,2,4]thiazolo[4,3-a]quinoline-1(2H)-one (3f) was among the most active but also has the lowest toxicity. In the anti-MES potency test, it showed median effective dose (ED(50)) of 12.3 mg/kg, median toxicity dose (TD(50)) of 547.5 mg/kg, and the protective index (PI) of 44.5, which is much greater than PI of the prototype drugs phenytoin, phenobarbital, carbamazepin, and valproate. Compound 3f was chosen for further evaluation. In phase III pharmacological test, the compound had median hypnotic dose (HD(50)) and median lethal dose (LD(50)) of 1204 mg/kg and >3000 mg/kg, respectively, thus demonstrating much greater margin of safety compared to prototype drugs. The compound 3f also showed significant oral activity against MES-induced seizures and low oral neurotoxicity in mice in phase IV pharmacological test. Possible structure-activity relationship was discussed.     

Cytotoxicity and detection of damage to DNA by 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c] quinazoline on human cancer cell line HeLa

Quinazolines - 1,3-benzodiazines are biological active compounds, which are used in the phamaceutical industry, in agriculture and in the medicine. As documented in the literature, many derivatives demonstrated anticancer activity and they act as multitarget agents. 3-(5-Nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c] quinazoline (NTCHMTQ) - a new synthetically prepared quinazoline derivative was the most effective derivative in our primary cytotoxic screening. In this study, we evaluated cytotoxic/antiproliferative activity of NTCHMTQ using human tumor cell line HeLa. Possible interaction of 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c] quinazoline with calf thymus DNA was tested by the DNA - modified screen - printed electrode. Quinazoline derivative acted cytotoxically on tumor cell line HeLa. The IC(100) value was 10 microg/ml. The IC(50) values was found to be less than 4 microg/ml, a limit put forward by the National Cancer Institute (NCI) for classification of he compound as a potential anticancer drug. Quinazoline at micromolar concentrations induced morphological changes and necrosis of HeLa cells. Using the DNA based electrochemical biosensor, we have not found damage to DNA under in vitro conditions at an incubation of the biosensor in mixture with quinazoline.     

Studies on adenosine A2a receptor antagonists: comparison of three core heterocycles

Piperazine and (R)-2-(aminomethyl)pyrrolidine derivatives of [1,2,4]triazolo[1,5-a][1,3,5]triazine have recently been shown to be potent and selective adenosine A(2a) receptor antagonists. We have replaced the triazolotriazine core structure with two different heterocyclic cores. One of these, the one deriving from [1,2,4]triazolo[1,5-c]pyrimidine, appears to be particularly effective and selected analogs from this series have been shown to be orally active in a mouse catalepsy model of Parkinson's disease.     

New V1a receptor antagonist. Part 2. Identification and optimization of triazolobenzazepines

Solid preclinical evidence links vasopressin to social behavior in animals, so, extensive work has been initiated to find new vasopressin V1a receptor antagonists which can improve deteriorated social behavior in humans and can treat the core symptoms of autistic behavior, as well. Our aim was to identify new chemical entities with antagonizing effects on vasopressin V1a receptors. Continuing our previous work, we found an in vitro and in vivo orally active V1a selective antagonist molecule (40) among [1,2,4]triazolo[4,3-a][1]benzazepines.     

Synthesis of some new [1,2,4]triazolo[3,4-b][1,3,4]thiadiazines and [1,2,4]triazolo[3,4-b][1,3,4] thiadiazoles starting from 5-nitro-2-furoic acid and evaluation of their antimicrobial activity

New series of fused 1,2,4-triazoles such as, 6-(aryl)-3-(5-nitrofuran-2-yl)-5,6-dihydro-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles 4-8, 6-(alkyl/aryl amino)-3-(5-nitrofuran-2-yl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles 9-13 and 6-(4-substituted phenyl)-3-(5-nitrofuran-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines 14-18 have been synthesized via the reaction of 4-amino-5-(5-nitrofuran-2-yl)-4H-1,2,4-triazole-3-thiol 3 with various reagents such as hetero aromatic aldehydes, alkyl/aryl isothiocyanates and 4-substituted phenacyl bromides, respectively. The structures of the newly synthesized compounds have been confirmed on the basis of elemental analysis and spectral studies. The newly synthesized triazolo derivatives have been investigated for their in vitro antibacterial activity. Most of the tested compounds showed interesting antibacterial activity against Staphylococcus aureus. Furthermore, the most potent antibacterial compounds 11-13 were evaluated for their in vitro cytotoxic activity against human cancer cell lines. It was found that compounds 11 and 13 showed higher cytotoxicity against Hep-G2 cell line as compared to standard.     

2-cyanoaminopyrimidines as a class of antitumor agents that promote tubulin polymerization

A series of 4-chloro-2-cyanoamino-6-fluoroalkylamino-5-phenylpyrimidines was prepared as a result of our efforts to modify a series of [1,2,4]triazolo[1,5-a]pyrimidines that proved to be potent anticancer agents with a unique mechanism of tubulin inhibition. On the cyanoamino nitrogen, a methyl group is optimal for activity among alkyl groups introduced. The structure-activity relationship for the rest of the molecule resembles that of [1,2,4]triazolo[1,5-a]pyrimidines. A lead compound (5) retained in vitro potency compared with TTI-237. In the mechanism of action studies, it behaved in the same manner as TTI-237. In addition, it is also capable of overcoming multidrug resistance due to P-gp. These findings strongly suggest that this series of 2-cyanoaminopyrimidines binds at the same site and in the same binding mode as TTI-237. Further modifications of the 2-cyanoamino group are underway.