6-Benzylidenethiazolo[3,2-b]-1,2,4-triazole-5(6H)-ones substituted withibuprofen: synthesis, characterization and evaluation of anti-inflammatory activity

In this study, the synthesis of 3-[1-(4-(2-methylpropyl)phenyl)ethyl]-1,2,4-triazole-5-thione (2) and its condensed derivatives 6-benzylidenethiazolo[3,2-b]-1,2, 4-triazole-5(6H)-ones (2a-u) are described. The structures of the compounds were elucidated by spectral and elemental analysis. In the pharmacological studies, anti-inflammatory activities of these compounds have been screened. Among the compounds examined, the compounds 2 and 2g possessed the most prominent and consistent activity. In gastric ulceration studies the synthesized compounds were generally found to be safe at a 200 mg/kg dose level.     

New 5-substituted thiazolo[3,2-b][1,2,4]triazol-6-ones: synthesis and anticancer evaluation

Following [2+3]-cyclocondensation reaction of 1,2,4-triazole-3(5)-thiol with N-arylmaleimides or with monochloroacetic acid and oxocompounds, N-(R-phenyl)-(6-oxo-5,6-dihydro[1,3]thiazol[3,2-b][1,2,4]triazol-5-yl)acetamides (1-5) and 5-ylidene-[1,3]thiazolo[3,2-b][1,2,4]triazol-6-ones (6-11) were synthesized as possible anticancer agents. Anticancer activity evaluation on the full panel of nearly 60 human cancer cell lines showed that synthesized compounds displayed this kind of activity on renal cancer, leukemia, colon cancer, breast cancer and melanoma cell lines. It was shown that 5-ylidene-[1,3]thiazolo[3,2-b][1,2,4]triazol-6-ones are characterized with more potent anticancer activity than respective amides. The structures of the compounds were determined by (1)H NMR, (13)C NMR and X-ray analysis.     

Design, synthesis and biological evaluation of substituted 11H-benzo[a]carbazole-5-carboxamides as novel antitumor agents

A series of novel 11H-benzo[a]carbazole-5-carboxamide derivatives were designed, synthesized and evaluated for their antitumor activity against human cancer A549 and HCT-116 cell lines. Most of the compounds showed potent antitumor activities, and compound 8 displayed remarkable in vitro and in vivo anticancer activity comparable to that of amonafide.     

N- and S-alpha-l-arabinopyranosyl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles. First synthesis and biological evaluation

First synthesis of N- and S-alpha-l-arabinopyranosyl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles is described. Antimicrobial screening of two selected regioisomeric compounds against Aspergillus fumigatus, Penicillium italicum, Syncephalastrum racemosum, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli are compared.     

Design & synthesis of N'-[substituted] pyridine-4-carbohydrazides as potential anticonvulsant agents

A series of N′-[substituted] pyridine-4-carbohydrazides were designed and synthesized keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and neurotoxicity. The anticonvulsant activity of the titled compounds was established after intraperitoneal administration in three seizure models, which include MES, scMET and 6 Hz model. The most active compound of the series was N′-[4-(4-fluorophenoxy)benzylidene]pyridine-4-carbohydrazide PCH 6, which showed a MES ED₅₀ value of 128.3 mg/kg and 6 Hz ED₅₀ value of 53.3 mg/kg in mice. The median toxic dose (TD₅₀) was 343.6 mg/kg, providing compound PCH 6 with a protection index of 2.67 in the MES test and 6.44 in 6 Hz test. A computational study was also carried out, including calculation of pharmacophore pattern, prediction of pharmacokinetic properties and docking studies.     

Synthesis and biological evaluation of dihydroindeno and indeno [1,2-e] [1,2,4]triazolo [3,4-b] [1,3,4]thiadiazines as antimicrobial agents

Two series of compounds namely, dihydroindeno and indeno [1,2-e] [1,2,4]triazolo [3,4-b] [1,3,4]thiadizines (9a-l & 11a-l) were synthesized by cyclocondensation between α-bromoindanones (7a-b) or/and α,α-dibromoindanones (8a-b) and various 3-alkyl/aryl-4-amino-5-mercapto-1,2,4-s-triazoles (3a-f) in methanol with an aim to explore their effect on in vitro growth of microorganism causing microbial infection. In vitro antibacterial activity was performed against four strains namely, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and antifungal activity against three fungal strains namely, Aspergillus niger, Aspergillus flavus, Penicillium species. Of all the compounds screened for activity some of the compounds were associated with considerably higher antibacterial and antifungal activity than commercial antibiotics.     

Novel 5,7-disubstituted 6-amino-5H-pyrrolo[3,2-b]pyrazine-2,3-dicarbonitriles, the promising protein kinase inhibitors with antiproliferative activity

New derivatives of pyrrolo[2,3-b]pyrazine were synthesized and tested on a panel of cultured human tumor cell lines. It was found that 6-amino-5-(3-chlorophenylamino)-7-(1-methyl-1H-benzo[d]imidazol-2-yl)-5H-pyrrolo[3,2-b]pyrazine-2,3-dicarbonitrile (4j) exhibited a significant antiproliferative activity: GI50 for cell lines RXF 393 (renal cancer) and BT-549 (breast cancer) were 14 and 82 nM, respectively. To identify possible molecular targets, docking of the most active compounds into the active sites of cyclin-dependent kinases was performed. Molecular modeling of the inhibitor-enzyme complexes showed the differences in the binding poses of new pyrrolo[2,3-b]pyrazine derivatives in the kinase ATP-binding site compared with known pyrrolo[2,3-b]pyrazine inhibitors called aloisines. The patterns of drug kinase interactions correlated well with antiproliferative activities of novel derivatives. Key interactions and binding mode of docked compounds are discussed.     

Synthesis and biological activity of new 2-amino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazines

Two series of 1-(6-chloro-1,1-dioxo-1,4,2-benzodithiazin-3-yl)-4-arylsemicarbazides 6-17 and 2-arylamino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazines 18-26 were prepared in order to evaluate their biological activity. Compounds 6 and 18-26 were tested for their in vitro cytotoxic potency against 12 human cancer cell lines. The compounds 6 and 19 were inactive, whereas triazolobenzodithiazines 18, 20-26 possess tumor growth inhibitory properties. The prominent methyl 8-chloro-2-(4-chlorophenylamino)-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazine-7-carboxylate (21) exhibited potency higher or comparable to cisplatin. Moreover, compounds 6, 9, 19 and 23-25 with structure similar to other chemotherapeutic agents were tested for their antibacterial activity and exhibited MIC and MBC against Staphylococcus aureus (3.9-31.5 microg ml).     

杂环胺代表物PhIP对大鼠不同组织脂质过氧化作用的影响

目的研究杂环胺代表物2-氨基-1-甲基-6-苯基-咪唑并[4,5-b]吡啶(PhIP)对雄性大鼠心、肺、肝、肾组织脂质过氧化作用的影响。方法对大鼠进行PhIP(5、10和15mg/kg)灌胃染毒,24 h后取大鼠心、肺、肝、肾组织,采用生化方法测定这4种组织的脂质过氧化作用相关指标。结果与对照组相比,15 mg/kg的PhIP可显著诱导大鼠心和肺组织超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPx)活性(P<0.05或P<0.01);而在肝组织中,10和15 mg/kg的PhIP显著抑制了这3种酶的活性(P<0.05或P<0.01)。肾组织中SOD、CAT和GPx活性的变化与对照组相比没有显著性差异。同时,随着PhIP浓度增加,大鼠心、肺、肝、肾组织中丙二醛(MDA)含量也随着增高,呈现浓度-效应关系,在较高浓度下(10和15 mg/kg的PhIP)与对照组相比差异有显著性(P<0.05)。结论 PhIP引起大鼠心、肺、肝、肾脂质过氧化,这种效应存在组织差异性。     

Synthesis and biological assessment of diversely substituted furo[2,3-b]quinolin-4-amine and pyrrolo[2,3-b]quinolin-4-amine derivatives, as novel tacrine analogues

The synthesis and pharmacological analyses of a number of furo[2,3-b]quinolin-4-amine, and pyrrolo[2,3-b]quinolin-4-amine derivatives are reported. Thus, we synthesized diversely substituted tacrine analogues 1–11 and 12–16 by Friedländer-type reaction of readily available o-amino(furano/pyrrolo)nitriles with suitable and selected cycloalkanones. The biological evaluation of furanotacrines1–11 and pyrrolotacrine13 showed that these are good, in the micromolar range, and highly selective inhibitors of BuChE. In the furanotacrine group, the most interesting inhibitor was 2-(p-tolyl)-5,6,7,8-tetrahydrofuro[2,3-b]quinolin-4-amine (3) [IC₅₀ (eqBuChE) = 2.9 ± 0.4 μM; IC₅₀ (hBuChE) = 119 ± 15 μM]. Conversely, pyrrolotacrines12 and 14 proved moderately equipotent for both cholinesterases, being 1,2-diphenyl-5,6,7,8-tetrahydro-1H-pyrrolo[2,3-b]quinolin-4-amine (12) the most potent for the inhibition of both enzymes [IC₅₀ (EeAChE) = 0.61 ± 0.04 μM; IC₅₀ (eqBuChE) = 0.074 ± 0.009 μM]. Moreover, pyrrolotacrine 12, at concentrations as low as 300 nM can afford significant neuroprotective effects against Aβ-induced toxicity. Docking studies show that compounds 3 and 12 bind in the middle of the AChE active site gorge, but are buried deeper inside BuChE active site gorge, as a consequence of larger BuChE gorge void. All these data suggest that these new tacrine analogues could be used for the potential treatment of Alzheimer’s disease.     

Pregnancy interceptive efficacy and biological profile of 3-amino-6,7-dimethoxy-1H-pyrazolo [3,4-b] quinoline (compound 85/83) in rodents

Administration of compound 85/83 during the peri- and post-implantation period intercepted pregnancy in hamster and guinea pig by parenteral route and in hamster by oral route also. The m.e.d. for hamster and guinea pig was 10 and 20 mg/kg, respectively; lower doses were less effective. Restricting the administration to early post-implantation schedule interrupted pregnancy partially in both species. The compound was, however, ineffective in rat and in the pre-implantation schedule (days 1-4 post-coitum) in hamster. When tested in vitro on growing trophoblasts at 13.8 x 10(-5) M concentration, it prevented growth and caused degeneration of the cells within 24 h; lower concentration (9.2 x 10(-5) M) was less effective. The compound was found to be devoid of estrogenic, antiestrogenic, progestational and antiprogestational properties in conventional bioassays. In hormone competition assays, its relative binding affinity (RBA) to estrogen receptor was negligible (0.002% of estradiol-17 beta), while for uterine cytosol progesterone receptors in rabbit and hamster was 0.06 and 0.08% of progesterone, respectively. The compound 85/83 appears to intercept pregnancy by interfering with development of trophoblast cells.     

Synthesis and biological activity of 6H-isoindolo[2,1-a]indol-6-ones, analogues of batracylin, and related compounds

Closely related to batracylin, 6H-isoindolo[2,1-a]indol-6-ones including 2-nitro- 13a, 2-amino- 14, and 2-diethylaminopropionamide derivative 16 as well as D-ring substituted 13b, 13c or A-ring substituted 13d and 20 analogues, were synthesised and evaluated against L1210 leukaemia. Subsequent treatment of 13b and 13c with N,N-diethylethylenediamine at 180 degrees C, led to compounds 17a and 17b arising from an unexpected opening of the pyrrolidinone ring and amidification of the keto group. Under the same conditions, the dichloro derivative 13d led to the monoalkyl compound 20 which was the most cytotoxic of the series.     

Studies on the synthesis and antibacterial activity of 3,6-disubstituted 1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles

Treating infections caused by drug-resistant bacterial strains constitutes one of the most essential challenges for medicine nowadays. A range of new derivatives of 1,2,4-triazolo[3,4-b]1,3,4-thiadiazole have been synthesized and evaluated for their in?vitro antimicrobial activity. Compounds 1-8 indicated high activity towards Gram-positive bacteria, which was up to 16 times more than currently used antibiotics. To the best of our knowledge, the derivatives obtained by us are the most active among the 3-aryl-6-arylamino-1,2,4-triazolo[3,4-b]1,3,4-thiadiazoles known until now.     

Synthesis and pharmacological assessment of diversely substituted pyrazolo[3,4-b]quinoline, and benzo[b]pyrazolo[4,3-g][1,8]naphthyridine derivatives

The synthesis and pharmacological analyses of a number of pyrazolo[3,4-b]quinoline and benzo[b]pyrazolo[4,3-g][1,8]naphthyridine derivatives are reported. We have synthesized the diversely substituted tacrine analogues 1-6, by Friedl?nder-type reaction of readily available o-amino-1-methyl-pyrazole-dicarbonitriles with cyclohexanone. The biological evaluation showed that pyrazolotacrines 1-6 are inhibitors of Electrophorus electricus acetylcholinesterase (EeAChE), in the micromolar range, and quite selective in respect to serum horse butyrylcholinesterase (eqBuChE) inhibition; the most interesting inhibitor is N-(5-amino-1-methyl-6,7,8,9-tetrahydro-1H-benzo[b]pyrazolo[4,3-g][1,8]naphthyridin-3-yl)acetamide (5) [IC(50) (EeAChE) = 0.069 ± 0.006 μM; IC(50) (eqBuChE) = 6.3 ± 0.6 μM]. Kinetic studies showed that compound 5 is a mixed-type inhibitor of EeAChE (K(i) = 155 nM). Inhibitor 5 showed a 45% neuroprotection value against rotenone/oligomycin A-induced neuronal death.     

Design, synthesis of 8-alkoxy-5,6-dihydro-[1,2,4]triazino[4,3-a]quinolin-1-ones with anticonvulsant activity

A new series of 8-alkoxy-5,6-dihydro-[1,2,4]triazino[4,3-a]quinolin-1-one derivatives were synthesized. Their anticonvulsant activities were evaluated by the maximal electroshock (MES) test, and their neurotoxicities were evaluated by the rotarod neurotoxicity test. The results showed that 8-heptyloxy-5,6-dihydro-[1,2,4]triazino[4,3-a]quinolin-1-one 5t was the most potent with median effective dose (ED(50)) value of 11.4 mg/kg, median toxicity dose (TD(50)) of 114.1 mg/kg, providing a protective index (PI=TD(50)/ED(50)) value of 10.0, which is much greater than the PI of the prototype drug carbamazepine (PI=6.4). To explain the possible mechanism of anticonvulsant activity, the compound 5t was tested in chemically induced seizures.     

Design, synthesis and biological activity of pyrazolo[1,5-a]pyrimidin-7(4H)-ones as novel Kv7/KCNQ potassium channel activators

Voltage-gated Kv7/KCNQ/M-potassium channels play a pivotal role in controlling neuronal excitability. Genetic reduction of KCNQ channel activity as a result of mutations causes various human diseases such as epilepsy and arrhythmia. Therefore, discovery of small molecules that activate KCNQ channels is an important strategy for clinical intervention of membrane excitability related disorders. In this study, a series of pyrazolo[1,5-a]pyrimidin-7(4H)-ones (PPOs) have been found to be novel activators (openers) of KCNQ2/3 potassium channels through high-throughput screening by using atomic absorption rubidium efflux assay. Based on structure-activity relationship (SAR), the substituted PPOs have been optimized. The 5-(2,6-dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl) pyrazolo[1,5-a]pyrimidin-7(4H)-one (17) was identified as a novel, potent, and selective KCNQ2/3 potassium channel opener by patch-clamp recording assay.     

Synthesis and biological activity of pyrazolothienotetrahydroisoquinoline and [1,2,4]triazolo[3,4-a]thienotetrahydroisoquinoline derivatives

1-Hydrazino-3-thioxo-5,6,7,8-tetrahydroisoquinoline-4-carbonitrile (3) was subjected to react with bifunctional compounds namely: acetylacetone, ethyl cyanoacetate, ethyl benzoylactate, diethylmalonate and ethyl acetoacetate to produce pyrazololthienotetrahydroisoquinoline derivatives 6-11. Also, heating of compound (3) with formic acid afforded triazolothienotetrahydroisoquinoline compound 5 which reacted with α-halogenated compounds to afford compounds 13a-e. Compound 13c when heated with triethylorthoformate afforded triazolo derivative 14. Also, compound 6 was used for synthesizing compounds 18-20. Representative compounds of the synthesized triazolo and pyrazolothienotetrahydroisoquinoline products were tested and evaluated as antimicrobial agents.     

Heterocyclic system containing bridgehead nitrogen atom: synthesis and pharmacological activities of some substituted 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles

Several 3,6-disubstituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadizoles were prepared by the condensation of 4-amino-3-aryl/aralkyl substituted-5-mercapto-1,2,4-triazoles 3(a-c) with various substituted aromatic/hetero aromatic acids through a single step reaction. Elemental analysis, IR, 1H NMR and mass spectral data confirmed the structure of the newly synthesized compounds. Synthesized triazolo thiadiazoles investigated for their antibacterial, antifungal, anti-inflammatory and analgesic activities. Some of the tested compounds showed moderate antimicrobial activity against various tested bacterial and fungal strains. None of the synthesized compounds have significant anti-inflammatory and analgesic activities.     

Synthesis and analgesic activity of 4-amino-1,2-dihydro-5-(2-hydroxyphenyl)-3H-pyrazol-3-ones and 5-amino-6-(2-hydroxyphenyl)pyrimidin-4(3H)-ones

4-Amino-1,2-dihydro-5-(2-hydroxyphenyl)-3H-pyrazol-3-ones 2a–c and 5-amino-6-(2-hydroxyphenyl)pyrimidin-4(3H)-ones 3a–f were synthesized from 4-methoxy- and 4-hydroxy-3-nitrocoumarins, and tested for analgesic activity upon oral administration to mice. Most of the compounds prepared exhibited analgesic activity which was superior to that of aminopyrine. In particular, 2a–c and 3a, d showed prominent activity which was 3–4.5 times as potent as that of aminopyrine.     

Synthesis, biological evaluation and docking studies of 4-amino substituted 1H-pyrazolo[3,4-d]pyrimidines

The synthesis of new 4-amino substituted pyrazolo[3,4-d]pyrimidines along with their activity in cell-free enzymatic assays on Src and Abl tyrosine kinases is reported. Some compounds emerged as good dual inhibitors of the two enzymes, showed antiproliferative effects on two Bcr-Abl positive leukemia cell lines K-562 and KU-812, and induced apoptosis, as demonstrated by the PARP assay. Docking studies have been also performed to analyze the binding mode of compounds under study and to identify the structural determinants of their interaction with both Src and Abl.