High-performance blue electroluminescent devices based on 2-(4-biphenylyl)-5-(4-carbazole-9-yl)phenyl-1,3,4-oxadiazole

An electron transporting moiety (1,3,4-oxadiazole) and a hole transporting moiety (carbazole) were combined to create 2-(4-biphenylyl)-5-(4-carbazole-9-yl)phenyl-1,3,4-oxadiazole (CzOxa), a three layer device with a configuration of ITO/TPD(50 nm)/CzOxa(40 nm)/AlQ(40 nm)/Mg0.9Ag0.1(200 nm)/Ag(80 nm) which exhibited a blue emission peak at approximately 470 nm (x = 0.14, y = 0.19) with a maximum luminance of 26,200 cd m(-2) at a drive voltage of 15 V and a maximum luminous efficiency of 2.25 lm W(-1).     

Optimized POCl3-assisted synthesis of 2-amino-1,3,4-thiadiazole/1,3,4-oxadiazole derivatives as anti-influenza agents

Although recent decades have witnessed the synthesis of 1,3,4-thiadiazoles via phosphorus POCl₃-promoted cyclization reaction, simultaneous access to 2-amino-1,3,4-thiadiazole and 2-amino-1,3,4-oxadiazole analogs remains unexpected and elusive. Herein, a detailed regiocontrolled synthesis of 2-amino-1,3,4-thiadiazoles in good to high yields with good regioselectivities from readily available thiosemicarbazides using POCl₃ was disclosed. Meantime, to establish a comprehensive structure–activity relationship, 2-amino-1,3,4-oxadiazole derivatives as single regioisomers were prepared via EDCI·HCl-triggered cyclization of the thiosemicarbazide intermediates. The in vitro anti-influenza assays proved that the selected compounds with the pyrazine/pyridine ring exhibited certain inhibitory activities against influenza A virus strains A/HK/68 (H3N2) and A/PR/8/34 (H1N1) in MDCK cells. Among them, N-(adamantan-1-yl)-5-(5-(azepan-1-yl)pyrazin-2-yl)-1,3,4-thiadiazol-2-amine (4j) was the most active compound, and exhibited favorable activity with EC₅₀ values of 3.5 μM and 7.5 μM, respectively. In addition, the molecular docking results explained the reason why compound 4j had dual inhibitory activity and revealed the reasonable binding mode of this compound with the M2-S31N and M2-WT ion channels. This compound had the potential to be further developed as an anti-influenza drug.     

Studies on pyrrolidinones. A convenient synthesis of 2-methyl-5-(5-oxo-1-benzyl-2-pyrrolidinyl)-1,3,4-oxadiazole

2-Methyl-5-(5-oxo-1-benzyl-2-pyrrolidinyl)-1,3,4-oxadiazole is easily obtained by dehydration of N-acetyl-1-benzylpyroglutamic acid hydrazide with a methanesulfonic acid/phosphoric anhydride mixture.     

A new convenient synthesis of 5-aryl-2-(arylamino)-1,3,4-oxadiazole derivatives

Electrical energy offers numerous benefits for conducting a synthesis, including increased reaction rates, yield enhancements and cleaner chemistries. 5-Aryl-2-(arylamino)-1,3,4-oxadiazoles were synthesised directly from acylthiosemicarbazide on the platinum electrode under controlled potential electrolysis in an undivided cell assembly in acetonitrile.     

A facile greener synthesis,antimicrobial evaluation and molecular modelling of new 4-aryl-2-(3-(2-(trifluoromethyl)phenyl)-1,8-naphthyridin-2-yl)phthalazin-1(2H)-one derivatives

Research on Chemical Intermediates - The synthesis of 4-aryl-2-(3-(2-(trifluoromethyl)phenyl)-1,8-naphthyridin-2-yl)phthalazin-1(2H)-ones was performed by cyclization of...     

Syntheses of substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles

Starting from readily available ethyl-4-nitropyrrole-2-carboxylate ( 1 ), substituted 1-methyl-2-(1,3,4-thiadiazol-2-yl)-4-nitropyrroles and 1-methyl-2-(1,3,4-oxadiazol-2-yl)-4-nitropyrroles were prepared. The reaction of 1 with diazomethane gave ethyl 1-methyl-4-nitropyrrole-2-carboxylate ( 2 ). Reaction of compound 2 with hydrazine hydrate afforded the corresponding hydrazide 3 . The reaction of 3 with formic acid yielded 1-(1-methyl-4-nitropyrrole-2-carboxyl)-2-(formyl)hydrazine ( 7 ). Refluxing of the latter with phosphorus pentasulfide in xylene yielded compound 6 in 40% yield. Reaction of compound 7 with phosphorus pentoxide afforded compound 9 . Reaction of compound 3 with 1,1′-carboxyldiimidazole in the presence of triethylamine yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-oxadiazoline-4(H)-5-one ( 11 ). Refluxing compound 3 with cyanogen bromide in methanol gave compound 12 . Compound 13 could be obtained through the reaction of compound 3 with carbon disulfide in basic medium. Alkylation of compound 13 afforded the correspanding alkylthio derivative 14 . Reaction of 1-methyl-4-nitropyrrole-2-carboxylic acid ( 15 ) with thiosemicarbazide and phosphorus oxychloride gave 2-amino-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 16 ). Sandmeyer reaction of compound 16 yielded 2-chloro-5-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazole ( 17 ). Refluxing of the latter with thiourea afforded 2-(1-methyl-4-nitro-2-pyrrolyl)-1,3,4-thiadiazoline-4(H)-5-thione ( 18 ). Alkylation of compound 18 gave the corresponding alkylthio derivative 19 . Oxidation of the latter with hydrogen peroxide in acetic acid yielded 2-(1-methyl-4-nitro-2-pyrrolyl)-5-methylsulfonyl-1,3,4-thiadiazole ( 20 ).     

Synthesis and pharmacological evaluation of 9(10H)-acridone bearing 1,3,4-oxadiazole derivatives as antimicrobial agents

In the present study a new acridone derivatives were synthesized. The newly synthesized compounds were characterized by IR, NMR and C, H, N, S analyses. All newly synthesized compounds were screened for their antibacterial (Staphylococcus aureus, Streptococcus viridans and Escherichia coil) and antifungal (Gibberela, Cercospora arachidicola, Physolospora piricola and Fusarium oxysporum) studies. The results revealed that all synthesized compounds have a significant biological activity against the tested microorganisms.     

2-Amino-4-(aminomethyl)thiazole-based derivatives as potential antitumor agents: design,synthesis, cytotoxicity and apoptosis inducing activities

Novel 2-amino-4-(aminomethyl)thiazole derivatives were designed and synthesized by a facile method including the Hantzsch construction of thiazole core followed by amidation and nucleophilic substitution steps. Bioassay results showed that 4-(tert-butyl)-N-[4-(piperazin-1-ylmethyl)thiazol-2-yl]-benzamide and 4-(tert-butyl)-N-{4-[(4-piperidinopiperidin-1-yl)methyl]thiazol-2-yl}benzamide possessed similar activities compared with 5-fluorouracil. The 4-piperidino-piperidin-1-yl-containing derivative also suppressed proliferation of cultured tumor cells by inducing apoptosis.     

Design and synthesis of oxaprozin-1,3,4-oxadiazole hybrids as potential anticancer and antibacterial agents

In the present study, we report design, synthesis and screening of new novel 5-substituted-2-mercapto-1,3,4-oxadiazole analogues appended to oxaprozin for their in vitro anticancer and antibacterial activity. The synthesised compounds were characterized using various spectroscopic techniques. Furthermore, the structure of 5b (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(ethylthio)-1,3,4-oxadiazole) was unequivocally confirmed by X-ray analysis. Among the series 5c (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(propylthio)-1,3,4-oxadiazole) showed most promising anticancer activity against A549 cancer cell line and all the reported analogues manifested satisfactory safety profiles against human normal cell line HEK293T. The products exhibited good antibacterial activity and among the tested 5j (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-([4-fluorobenzyl]thio)-1,3,4-oxadiazole) exhibited most potent.     

2-(1H-苯并咪唑-2-基)-5-取代-1,3,4-噁二唑化合物的合成及抑菌活性

以苯并咪唑-2-甲酸、水合肼、取代苯基异硫氰酸酯和取代苯甲酸等为原料,经多步反应合成了16种2-(苯并咪唑-2-基)-5-取代苯基-1,3,4-噁二唑和2-(苯并咪唑-2-基)-5-取代苯胺基-1,3,4-噁二唑新化合物,并考察了微波辐射对反应的影响.产物结构利用IR,1H NMR,13C NMR和元素分析确证.用生长速率法测试了目标化合物对番茄灰霉病菌和小麦菌核病菌的离体抑制活性,结果表明3种化合物对番茄灰霉病菌有很高的抑制活性,其EC50分别为2.55,6.34和5.12μg/mL,活性高于对照药剂多菌灵(EC50=7.40μg/mL).     

Synthesis and in vitro antitumor activity of 1,3,4-oxadiazole derivatives based on benzisoselenazolone

A series of novel 1,3,4-oxadiazole derivatives based on benzisoselenazolone has been prepared and tested for antiproliferative activity in vitro against the cells of human cancer cell lines: SSMC-7721 (human liver cancer cell), MCF-7 (human breast cancer cell) and A549 (human lung cancer cell). All the compounds obtained exhibited antiproliferative activity and showed selective cytotoxicity against different cancer cells. Compounds 7d and 7i showed significant antiproliferative activities against MCF-7 cells, with IC50 values of 1.07 and 1.76?μM respectively. Compound 7d were found to be the most potent compound against SSMC-7721 cells, with IC50 values 4.46?μM.     

N-Arylation of a hindered indoline as a route to 2-(2-methyl-1-(4-oxo-3,4-dihydrophthalazin-1-yl)-1H-indol-3-yl)acetic acid derivatives

A convenient synthesis of 2-(2-methyl-1-(4-oxo-3,4-dihydrophthalazin-1-yl)-1H-indol-3-yl)acetic acid derivatives is described using a microwave-promoted multi-step S_NAr reaction. The desired products were found to exhibit atropisomerism.     

Synthesis and Crystal Structure of N''-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl) acetohydrazide

N'-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl)acetohydrazide was synthesized by the reaction of 4-fluorobenzaldehyde with 2-(1H-1,2,4-triazole-1-yl) acetohydrazide. The structure was confirmed via elemental analysis, MS,1H NMR, IR, and X-ray diffraction. It crystallized in a monoclinic system with space group P2 ( 1 ), a =0.4905(1) nm, b=0.8160(2) nm, c=1.4105(3) nm,β=93.33(3)°,Z=2, V=0.5636(2) nm3, Dc =1.457 Mg/m3,μ=0.112 mm-1 , F(000) =256, and final R1 =0. 0685. Several intermolecular hydrogen-bond interactions existed in the crystal structure, facilitating the stabilization of the compound.     

Synthesis and antimycobacterial screening of new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives

This article demonstrates the synthesis, characterization and the study of in vitro antitubercular activities of twenty four new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives(8a–x). The antitubercular activity of the compounds against Mycobacterium tuberculosis H37Rv(MTB) revealed that 2-chloro-N-(4-(5-(4-chlorophenyl)-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)benzamide(8n) is the most promising lead molecule with a MIC of1.56 mg/m L, while the corresponding unsubstituted benzamide derivative(8o) is the next most active molecule with a MIC of 3.13 mg/m L. Interestingly, the pyrazole intermediate 5b containing chlorophenyl and N-acylcarbohydrazide substituents also showed significant activity(MIC = 3.13 mg/m L). Further, the active molecules did not show toxicity against a normal NIH 3T3 cell line, signifying their suitability for further drug development.     

Synthesis of stereoisomeric 4-(2-methylindolin-1-yl)- and 4-(2-methylindol-1-yl) derivatives of glutamic acid

The reaction of dimethyl (2S,4RS)-N-phthaloyl-4-bromoglutamate with 2-methylindoline afforded diastereomeric 4-(2-methylindolin-1-yl)-(S)-glutamic acid derivatives, whose oxidation gave rise to 4-(2-methylindol-1-yl)-(S)-glutamic acid derivatives.     

Synthesis,Crystal Structure and Antifungal Activity of 2-((2-Fluorobenzyl)thio)-5-(pyridin-4-yl)-1,3,4-oxadiazole

The title compound 2-((2-fluorobenzyl)thio)-5-(pyridin-4-yl)-1,3,4-oxadiazole(C_(14)H_(10)FN_3OS) was synthesized,and its structure was confirmed by ~1H NMR,MS,elemental analyses and X-ray diffraction. It crystallizes in the monoclinic system,space group P21/n with a = 11.541(16),b = 8.226(12),c = 13.683(19) ?,β = 94.872(17)o,V = 1294(3) ?~3,Z = 4 and R = 0.0648 for 2198 observed reflections with I 2σ(I). The preliminary biological test shows that the title compound has good activity against Pythium ultimum with inhibitory to be 100%.     

New general synthesis of tetrahydro-1,2,4,5-tetrazin-3(2H)-one derivatives and stable 3,4-dihydro-3-oxo-1,2,4,5-tetrazin-1(2H)-yl radical derivatives

Reactions of 2-chloroformylhydrazones of aromatic aldehydes or ketones 2 with various hydrazines were converted to monocarbonohydrazone derivatives 3 or 5 and/or tetrahydro-1,2,4,5-tetrazin-3(2H)-one derivatives 6 , 7 . By oxidation with lead dioxide, compounds 6 were transformed into stable 3,4-dihydro-3-oxo-1,2,4,5-tetrazin-1(2H)-yl radical derivatives 8 .