Synthesis, anti-inflammatory activity, and QSAR study of some Schiff bases derived from 5-mercapto-3-(4′-pyridyl)-4H-1,2,4-triazol-4-yl-thiosemicarbazide

The purpose of this research is to synthesize better anti-inflammatory compounds derived from 5-mercapto-3-(4′-pyridyl)-4H-1,2,4-triazol-4-yl-thiosemicarbazide (5). 2-Substituted-N-[3-(pyridin-4-yl)-5-sulfanyl-4H-1,2,4-triazol-4-yl]hydrazine carbothioamide derivatives (6a–j)/(7a–e) are synthesized by the condensation of 5 with variously substituted aromatic aldehydes/1H-indole-2,3-diones, respectively, under conventional and microwave irradiation methods. The microwave method is found to be superior with higher chemical yields, tremendous reduction in time, and is environmentally benign as compared to conventional heating method. The chemical structures of the newly synthesized compounds (6/7) have been confirmed by IR, ¹H NMR, and ¹³C NMR spectra and have been evaluated for anti-inflammatory activity by carrageenan-induced acute paw edema method in rats.     

Synthesis and analgesic activity of new pyridine-based heterocyclic derivatives

A series of new heterocyclic derivatives having a pyridine nucleus were synthesized. 4-(5-(2-Chlorophenyl)-4H-1,2,4-triazol-3-yl)pyridine (7c) and 4-(5-(2-Nitrophenyl)-4H-1,2,4-triazol-3-yl)pyridine (7d) presented the best analgesic profie of this series in hot-plate, tail-flick, and formalin-induced licking tests, which was partially prevented by pretreatment with mecamylamine, a nicotinic receptor antagonist.     

Synthesis,in vitro cytotoxicity,and anti-microbial studies of 1,4-bis(4-substituted-5-mercapto-1,2,4-triazol-3-yl)butanes

Synthesis and evaluation of cytotoxicity and anti-microbial activity of a series of 1,4-bis(4-substituted-5-mercapto-1,2,4-triazol-3-yl)butane derivatives comprising thioether functionality and other pharmacophore modifications are described. All the newly synthesized compounds were characterized by IR, NMR, elemental analyses, and mass spectral studies. The compounds 4a–f, 5a–f, and 6a–f were evaluated for in vitro cytotoxicity potential using the standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against a panel of three human cancer cell lines: Lung carcinoma A-549, Colon carcinoma HT-29, and Breast Cancer MDA MB-231. All the compounds were subjected to in vitro anti-bacterial activity against Bacillus subtilus (ATCC 6633), Staphylococcus aureus (ATCC-25923), Escherichia coli (ATCC-25922), and Pseudomonas aeruginosa (ATCC-27853) and their minimal inhibitory concentrations were determined.     

Synthesis and anti-inflammatory activity evaluation of novel 3-alkyl-6-(4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-4-yl)-3,4-dihydro-2<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">e</Emphasis>][1,3]oxazine derivatives

To discover new compounds with anti-inflammatory activity, a series of novel 3-alkyl-6-(4H-1,2,4-triazol-4-yl)-3,4-dihydro-2H-benzo[e][1,3]oxazine derivatives were synthesized and their structures were confirmed by spectroscopic techniques. In vivo anti-inflammatory activity of the synthesized compounds was determined using the xylene-induced mouse ear edema model. 3-Heptyl-6-(4H-1,2,4-triazol-4-yl)-3,4-dihydro-2H-benzo[e] [1,3]oxazine and 3-p-tolyl-6-(4H-1,2,4-triazol-4-yl)-3,4-dihydro-2H-benzo[e][1,3]oxazine demonstrated higher anti-inflammatory activity (74.04?% and 64.99?%, respectively) at 0.5?h after intraperitoneal administration than the reference drug ibuprofen (62.65?%). Further, the time of peak effect after oral administration was 4?h for both compounds. Our results identify new compounds with anti-inflammatory activity in vivo that may have improved safety/side effect profiles relative to the currently approved nonsteroidal anti-inflammatory drugs.     

Synthesis and biological activity studies of new hybrid molecules containing tryptamine moiety

The synthesis of N′-(4-substitutedphenylsulfonyl)-2-{4-[2-(1H-indol-yl)ethyl]-3-(4-chlorobenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}acetohydrazides (3a–c), 2-{4-[2-(1H-indol-3-yl)ethyl]-3-(4-chlorobenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}-N′-aryl methylidene acetohydrazides (4a–f) and 4-[2-(1H-indol-3-yl)ethyl]-5-(4-substitutedbenzyl)-2-[(5-sulfanyl-1,3,4-oxadiazol-2-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-ones (5a, b) was performed starting from the corresponding acid hydrazides (2a, b) which was reported earlier. The treatment of 1,3,4-oxadiazole derivatives (5a, b) with hydrazine hydrate produced 4-amino-5-sulfanyl-4H-1,2,4-triazol-3-yl derivatives (6a, b). Then, compound 6b was converted to the corresponding Schiff base (7) by the treatment with anisaldehyde. The synthesis of 5-(4-chlorobenzyl)-4-[2-(1H-indol-3-yl)ethyl]-2-[(4-benzyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-one (8) and 5-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-2-[(4-benzyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-one (10) was carried out by the reaction of acid hydrazides (2a, b) with aryl iso(thio)cyanates either via the formation of the intermediates (9a, b) (for 10) or direct cyclization (for 8). 1,3-Oxa(thia)zol-2(3H)-ylidene]acetohydrazide derivatives (11a, b) were obtained by the reaction of 9a, b with 4-chlorophenacyl bromide. All newly synthesized compounds were screened for their antimicrobial activities and some of which was found to be active against the test microorganisms.     

Potential antihypertensives. Synthesis of 6-substituted-N-(4H-1,2,4-triazol-4-yl)-3-pyridazinamines and 3-substituted-6-(3,5-dimethyl-1H-1,2,4-triazol-1-yl)pyridazines

A series of 6-substituted-N-(4H-1,2,4-triazol-4-yl)-3-pyridazinamines [(II), Scheme 1] and 3-substituted-6-(3,5-dimethyl-1H-1,2,4-triazol-1-yl) pyridazines [(XII), Scheme 3-5] were synthesized. The compounds were evaluated for their oral antihypertensive activity in rats (SHR) and only some compounds of structure (XII) induced a moderate decrease in systolic blood pressure.     

Studies on fused heterocyclic 3,6-disubstituted-1,2,4-triazolo-1,3,4-thiadiazoles: synthesis and biological evaluation

In this study, a series of 3,6-disubstituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazoles (5a–t) were synthesized by condensing 4-amino-3-mercapto-(4H)-1,2,4-triazoles (4a–c) with different aromatic or aroyl acids through one-pot reaction. The compounds were evaluated for their anti-inflammatory, analgesic, ulcerogenic, and lipid peroxidation actions. Some of the newly synthesized compounds showed very good anti-inflammatory activity with low GI toxicity and reduced lipid peroxidation. These compounds also showed interesting profile of analgesic activity in acetic acid-induced writhing test. The findings of the study indicate that the synthesized compounds have superior GI safety profile along with reduction in lipid peroxidation as compared to that of the standard.     

Synthesis and cytotoxicity of bis-1,3,4-oxadiazoles and bis-pyrazoles derived from 1,4-bis[5-thio-4-substituted-1,2,4-triazol-3-yl]-butane and their DNA binding studies

A new series of 1,4-bis[5-(5-mercapto-1,3,4-oxadiazol-2-yl-methyl)-thio-4-substituted-1,2,4-triazol-3-yl]-butane 7-12 and 1,4-bis[5-(1-oxo-1-(3,5 dimethyl pyrazol-1-yl)-methyl)-thio-4-substitued-1,2,4-triazol-3-yl]-butane 13-18 were prepared from 1,4-bis(5[hydrazinocarbonylmethylthio]-4-substituted-1,2,4-triazol-3-yl) butane based derivativess were synthesized 1-6. All the synthesized compounds were characterized by IR, NMR and Mass spectral studies. The synthesized compounds 7-18 were screened for in-vitro cytotoxicity potential using the standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against a panel of three human cancer cell lines: Lung carcinoma A-549, colon carcinoma HT-29 and breast cancer MDA MB-231. DNA binding studies were conducted for three potent molecules by absorption titration method.     

Synthesis and pharmacological evaluation of novel 4-isopropylthiazole-4-phenyl-1,2,4-triazole derivatives as potential antimicrobial and antitubercular agents

A series of novel 4-isopropylthiazol-4-phenyl-1,2,4-triazol derivatives, N′-(substituted benzylidene)-2-(5-(4-isopropylthiazol-2-yl)-4-phenyl-4H-1,2,4-triazol-3-ylthio)acetohydrazides 4a–e, 4-isopropylthiazol-2-yl-4′-phenyl-4′H-1′, 2′,4′-triazol-3′-ylthio (substituted methyl benzylidene) acetohydrazides 5a–f, 3-(4-isopropylthiazol-2-yl)-4-phenyl-5-(5-substituted-1,3,4-oxadiazol-2-ylthio)-4H-1,2,4-triazole derivatives 6a–f and N-acetyl-5′-(4-isopropylthiazol-2-yl)-4′-phenyl-4′H-1,2,4-triazol-3′-ylthio) acetohydrazide 7 were synthesized and characterized by spectroscopy, elemental, and mass spectral analysis. These compounds were evaluated for their preliminary in vitro antibacterial, antifungal, and antitubercular activity against Mycobacterium tuberculosis (M. tuberculosis) H37Rv strain by broth dilution assay method. All the compounds exhibited moderate to significant antibacterial and antifungal activities. Results of the antitubercular screening against Mycobacterium tuberculosis H37Rv showed that compounds 4c and 6c exhibited good antitubercular activity when compared with first line drug isoniazid.     

Simple and efficient synthetic routes to bioactive s-triazinyl dithiocarbamate derivatives

Series of 2,4-diarylamino-6-[N-(3′-methylphenyl)dithiocarbamoyl]-s-triazines (4a–l) and 2,4-bis[N-(3′-methylphenyl)dithiocarbamoyl]-6-arylamino-s-triazines (7a–l) were synthesized by two different synthetic routes. In the first route (A), 2,4,6-tricholoro-s-triazine (1) was condensed with N-(3-methylphenyl)ammoniumdithiocarbamate to afford compounds 3 or 6, which on reaction with different aryl amines afforded compounds 4a–l or 7a–l. In the second route (B), condensation of 1 with different aryl amines yielded compounds 2a–l or 5a–l. On further treatment with N-(3-methylphenyl)ammoniumdithiocarbamate these afforded compounds 4a–l or 7a–l. The newly synthesized compounds 4a–l and 7a–l were characterized by elemental analyses, infrared (IR), and ¹H nuclear magnetic resonance (NMR) spectroscopic investigation. All the products were evaluated for their antibacterial and antifungal activity.     

Synthesis of 6-(3-substituted-4H-1,2,4-triazol-4-yl)-2-phenylbenzo[d]oxazoles as potential anticonvulsant agents

A series of 6-(3-substituted-4H-1,2,4-triazol-4-yl)-2-phenylbenzo[d]oxazoles was synthesized. The anticonvulsant effect and neurotoxicity of the compounds were calculated with maximal electroshock (MES) test, subcutaneous pentylenetetrazole (Sc-PTZ), and rotarod tests in intraperitoneally injected mice. Among the synthesized compounds, compound 2-phenyl-6-(4H-1,2,4-triazol-4-yl)benzo[d]oxazole (3a) could be considered the potentially most useful and safe therapeutic compound, with ED₅₀ = 29.6 mg/kg, TD₅₀ = 285 mg/kg, and PI = 9.7. Its neurotoxicity was the lowest of all the synthesized compounds and was also markedly lower than that of the reference drug carbamazepine with PI value of 6.4.     

3-取代三唑醇类化合物的合成及抗真菌活性

目的设计合成1-(1H-1,2,4-三唑-1-基)-2-(2,4-二氟苯基)-3-烷氧基苯基哌嗪-2-丙醇和1-(1H-1,2,4-三唑-1-基)-2-(2,4-二氟苯基)-3-取代硫醚-2-丙醇化合物,并进行体外抗真菌活性测试.方法以间二氟苯为起始原料,经多步反应,得到中间体环氧化物甲烷磺酸盐,再与各种烷氧基苯基哌嗪和取代硫醇开环得到目标化合物,按国际标准抗真菌敏感性实验方法测定其体外抗真菌活性.结果共合成12个(其中11个为新化合物)目标化合物,经元素分析,1H-NMR和IR确证结构,其中4个化合物的抗真菌活性强于对照品氟康唑和酮康唑.结论含烷氧苯基哌嗪侧链的三唑醇类化合物具有较强的抗真菌活性.     

Studies on some N-bridged heterocycles derived from bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes

A series of bis-[4-amino-5-mercapto-1,2,4-triazol-3-yl] alkanes have been synthesized and were converted into bis-[1,2,4-triazolo[3,4-b]-1,3,4-thiadiazol-4-yl] alkanes. The newly synthesized compounds were characterized by analytical IR, NMR and mass spectral studies. Some of the newly synthesized compounds were screened for their antibacterial properties and exhibited activity with MIC in the range 3-12.5 micrograms/ml.     

Design and synthesis of 3-[3-(substituted phenyl)-4-piperidin-1-ylmethyl/-4-morpholin-4-ylmethyl-4,5-dihydro-isoxazol-5-yl]-1H-indoles as potent anti-inflammatory agents

The synthesis of new indole derivatives bearing isoxazoline moiety (3a–d and 4a–d) has been described. IR, ¹H NMR, and mass spectral data supported the structures of synthesized compounds. The compounds were tested in vivo for their anti-inflammatory activity by carrageenin-induced rat paw edema method. The compounds that showed good anti-inflammatory activity were screened for their ulcerogenic and lipid peroxidation activities. The most active compound of this series is 3-[3-(4-methoxyphenyl)- 4-morpholin-4-ylmethyl)-4,5-dihydro-isoxazol-5yl]-1H-indole 4d.     

Synthesis,anti-inflammatory,analgesic, and antibacterial activities of some triazole,triazolothiadiazole, and triazolothiadiazine derivatives

This study is concerned with the synthesis of new 1,2,4-triazoles, 1,3,4-thiadiazoles, and 1,3,4-thiadiazines derivatives. Derivatives 3a–i were obtained by condensation of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole 1 with the appropriate aldehyde. Compounds 4a–i were synthesized in a one pot reaction involving compounds 3a–i, formaldehyde, and morpholine. Condensation of compound 1 with the appropriate acids or 4-substituted phenacyl bromide gave compounds 6a–d and 8a–f respectively. The chemical structures of the newly synthesized derivatives were elucidated using different spectral and elemental methods of analysis. All compounds were evaluated for their anti-inflammatory activity and the most potent derivatives were tested for their analgesic activity using indomethacin as a reference drug. In addition, ulcerogenicity and LD₅₀ for the most active compounds were evaluated. Moreover, the antibacterial activities of the newly synthesized derivatives were investigated.     

Design,synthesis and biological evaluation of novel 1,2,3-triazole analogues of Imidazo-[1,2-a]-pyridine-3-carboxamide against Mycobacterium tuberculosis

Twenty-eight novel 1,2,3-triazole analogues of imidazo-[1,2-a]-pyridine-3-carboxamide were designed and synthesized based on hybridization approach. The structure of the final compounds are characterized using ¹HNMR, ¹³CNMR, LCMS and elemental analyses and are screened in vitro for anti-tubercular activity using low-oxygen recovery assay (LORA) non-replicating and using microplate alamar blue assay (MABA) against replicating M. tuberculosis. MIC was determined. From the obtained results, it was observed that, among (2,7-dimethylimidazo[1,2-a]pyridin-3-yl)(4-((1-subtituted phenyl-1H-1,2,3-triazol-4-yl)methyl)piperazin-1-yl)methanones and (6-chloro-2-methylimidazo[1,2-a]pyridin-3-yl)(4-((1-substituted phenyl-1H-1,2,3-triazol-4-yl)methyl)piperazin-1-yl)methanones, compounds with substitution at para position with electron electron releasing groups exhibited the best activity (< 34 μg/mL). Amidst, (2,7-dimethylimidazo[1,2-a]pyridin-3-yl)(4-(2-(4-alkyl/substituted aryl-1H-1,2,3-triazol-1-yl)ethyl)piperazin-1-yl)methanones and (6-chloro-2-methylimidazo[1,2-a]pyridin-3-yl)(4-(2-(4- alkyl/substituted aryl -1H-1,2,3-triazol-1-yl)ethyl)piperazin-1-yl)methanones, compounds with long alkyl chain or cyclo propyl group were most active (< 21 μg/mL) in MABA method against the tested strain of MTB. Compound 10b emerged to be the most active compound in MABA and LORA with MIC values 13.74 and 24.63 μg/mL respectively. In-silico ADMET parameters were also predicted for the significantly active compound. Finally, molecular docking study was carried out to predict the feasible binding pattern of the most active compound at the active site of enoyl acyl carrier protein reductase from Mycobacterium tuberculosis (PDB-4TZK) using Glide module of Schrodinger software.     

Synthesis of 2-substituted-6-(4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-4-yl)benzo[<Emphasis Type="Italic">d</Emphasis>]oxazoles as potential anticonvulsant agents

A series of 2-substituted-6-(4H-1,2,4-triazol-4-yl)benzo[d]oxazoles were synthesized. The anticonvulsant effect and neurotoxicity of the compounds (intraperitoneally) were evaluated with the maximal electroshock (MES) test, subcutaneous pentylenetetrazole (sc-PTZ), and rotarod tests in mice. 2-Phenyl-6-(4H-1,2,4-triazol-4-yl)benzo[d]oxazole (3g) was the most active and also had the lowest toxicity. In the anti-MES potency test, it showed median effective dose (ED₅₀) of 29.5 mg/kg, a median toxicity dose (TD₅₀) of 285 mg/kg, and a protective index (PI) of 9.7, which is greater than the reference drug, carbamazepine, which has a PI of 6.4.     

Potential anti-inflammatory activity and ulcerogenicity study of some novel pyrimido[4′,5′:4,5]pyrimido[1,6-<Emphasis Type="Italic">a</Emphasis>]azepine derivatives

A series of novel tricyclic pyrimido[4′,5′:4,5]pyrimido[1,6-a]azepine derivatives were synthesized using the starting compound 3-amino-1-oxo-2-phenyl-5-(pyrrolidin-1-yl)-1,2,4a,5,6,7,8,9-octahydropyrimido[1,6-a]azepine-4-carbonitrile 4. This series includes the 3-aryl derivatives 6a, b, the 3-cycloaminoalkyl derivatives 8a–f, the 3-mercaptomethyl derivatives 10 and 11a, b, the 2-cycloaminomethyl derivatives 13a–c, the 1-cycloamino derivatives 15a–c and the 1-amino derivative 16. The structures of the newly synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, mass spectroscopy and elemental analyses. The anti-inflammatory activity of all newly synthesized compounds was evaluated using the carrageenan-induced paw oedema test in rats using diclofenac sodium as the reference drug. Ulcer indices for the most active compounds were calculated. The 3-mercaptomethylacetic acid derivative 10 was the most active compound, showing activity comparable to diclofenac sodium with minimal ulcerogenic effect while the rest of the tested compound exhibited moderate anti-inflammatory activity.     

Anticonvulsant and neurotoxicity evaluation of 5-(un)-substituted isatinimino derivatives

Various Schiff bases were prepared by reacting 5-(un)-substituted isatin with some heterocyclic compounds, viz., N-[4-(4'-chlorophenyl-thiazol-2-yl] semicarbazide, 3-amino-2-methylmercaptoquinazolin-4-one, 3-(4'-pyridyl)-4-amino-5-mercapto-4(H)-1,2,4-triazole and 4-(4'-chlorophenyl)-6-(4"-methylphenyl)-2-aminopyrimidine. The compounds were evaluated for anticonvulsant and neurotoxic properties. The compound 3-(3',4'-dihydro-2'-methylmercapto-4'-oxoquinazolin-3'-yl) iminoisatin (3) emerged as the most active analogue showing anti-MES and anti-PTZ activities better than valproic acid. All the compounds showed lower neurotoxicity than phenytoin and carbamazepine.     

Synthesis and antifungal evaluation of 6-(N-arylamino)-7-methylthio-5,8-quinolinediones

A series of 6-(N-arylamino)-7-methylthio-5,8-quinolinedione derivatives4a-4l was newly synthesized for the evaluation of antifungal activity. 6-(N-Arylamino)-7-methylthio-5,8-quinolinediones were prepared by regioselective nucleophilic substitution of 6,7-dichloro-5,8-quinolinediones with arylamines in the presence of Ce³⁺, and Na₂S/dimethylsulfate. The MIC values of4a-4l were determined for antifungal susceptibilityin vitro againstCandida species by agar streak method. The derivatives4a-4l had generally potent antifungal activities against all human pathogenic fungi. Especially they had the most potent activity againstC. krusei at 12.5≈0.8 μg/ml. Compounds4d, 4g, 4h, 4j and4k had more potent antifungal activities than fluconazole. Compounds4g and4h completely inhibited the fungal growth at 0.8≈6.3 μg/ml against allCandida species, while fluconazole inhibited the growth at 25 μg/ml. The compounds such as4g and4h containing an N-(4-bromo-2-methylphenyl)- or N-(4-bromo-3-methylphenyl)amino substituent exhibited the most potent antifungal activities.