Synthesis and In Vitro Anticancer Activity of Novel 1,3,4‐Oxadiazole‐Linked 1,2,3‐Triazole/Isoxazole Hybrids

A series of new 1,3,4‐oxadiazole‐linked 1,2,3‐triazole/isoxazole derivatives were designed and synthesized. All the synthesized compounds were screened for in vitro anticancer activity against four human cancer cells: HeLa (cervical), MDA‐MB‐231 (breast), DU‐145 (prostate), and HEPG2 (liver). Among 17 compounds tested, 7a , 7c , and 7d showed potent activity toward four cell lines.     

Synthesis,Characterization, and Antimicrobial Screening of Ethylene‐Spaced Bis‐heterocycles

A new class of ethylene‐spaced bis‐heterocycles that was synthesized in a simple and efficient method from the one‐pot, three‐component reaction of amine 2 , propargyl halide 3 , and indolyl azide 1 in water is described. The identities of these compounds were confirmed following elemental analysis, IR, ¹H, ¹³C NMR, and mass spectral studies. All the title compounds exhibited pronounced in vitro antibacterial and antifungal activities.     

Synthesis of New Hybrid Heterocyclic Compounds Having 1,2,3‐Triazole and Isoxazole via Click Chemistry

A simple and highly efficient method for the regioselective synthesis of isoxazolyl‐1,4‐disubstituted‐1,2,3‐triazoles 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l in good to excellent yields from terminal alkynes having isoxazole scaffold 4a , 4b , 4c and various azides through Cu(I)‐catalyzed 1,3‐dipolar cycloaddition is described. The reaction proceeds smoothly in 1:1 mixture of t‐BuOH and water at RT. The structures of all newly synthesized hybrid heterocycles are established on the basis of spectral data ir, ¹H nmr, mass, and elemental analysis.     

Synthesis,Characterization, and In Vitro Antimicrobial Activity of Methyleneamine‐Linked Bis‐heterocycles

A new class of methyleneamine‐linked bis‐heterocycles that exhibit antimicrobial activity was synthesized. Bromination of 1 followed by condensation with thiourea gave 3 . The reaction of 3 with propargyl bromide in dry toluene under inert atmosphere led to the formation of 4 . Its subsequent reaction with different nitrile oxides using CuSO₄.5H₂O–sodiumascorbate system in a 2:1 mixture of water and tert‐butyl alcohol yielded the title compounds 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k , 6l in good yields. The identities of these compounds were confirmed following elemental analysis, IR, ¹H, ¹³C NMR, and mass spectral studies. All the title compounds exhibited pronounced in vitro antibacterial and antifungal activities.     

Synthesis and In Vitro Cytotoxic Activity of Novel Triazole‐Isoxazole Derivatives

New derivatives of triazole‐isoxazole were synthesized through a four‐step reaction starting from various ethyl 4‐aryl‐2,4‐dioxobutanoate derivatives. Finally, all compounds were examined by MTT assays for cytotoxic activity in two human breast cancer cell lines (MCF‐7 and T‐47D).     

Ultrasound Assisted Synthesis of Some Novel Bis‐Pyridazine Derivatives

Bis‐enaminone 3 was coupled with aryldiazonium chlorides 4a , 4b to afford the bis‐arylhydrazonopropanals 6a , 6b . Compounds 6a , 6b could be utilized for the synthesis of a variety of bis‐(dimethyl 2,3‐dihydropyridazine‐3,4‐dicarboxylate), bis‐(pyridazin‐3(2H)‐one), bis‐(2,3‐dihydropyridazine‐4‐carbonitrile) and bis‐(3‐imino‐2,3‐dihydropyridazine) derivatives, under ultrasonic irradiation. A comparative study of aforementioned reactions was carried out under conventional method as well as under ultrasonic irradiation conditions.     

A New Sustainable Strategy for Synthesis of Novel Series of Bis‐imidazole and Bis‐1,3‐thiazine Derivatives

An expeditious, eco‐friendly, and efficacious protocol was achieved for the preparation of bis‐imidazoles and bis‐1,3‐thiazines from the reaction of tetracyanoethylene with dialdehydes or bis‐thiosemicarbazones, respectively. Merely mixing and sonicating the starting materials furnishes the desirable products in considerable yields. This reaction smoothly proceeded and presented many merits, over conventional and mechanochemical approaches, including simple experimental workup procedure, no by‐products, and short reaction time. Moreover, the protocol scoring admirably in various green metrics, as a consequence, shows these approaches to be an ideal sustainable and green process.     

Synthesis and Cytotoxicity Evaluation of Novel Andrographolide‐1,2,3‐Triazole Derivatives

A series of new andrographolide‐1,2,3‐triazole derivatives, 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , were synthesized from a natural bioactive labdane type diterpenoid, andrographolide. All the derivatives were screened against human cancer cell lines MCF7, MDA‐MB‐231, COLO205, HepG2, K562, Hela, and HEK293 to evaluate their cytotoxic activity. All the compounds showed anticancer activity selectively against K562 cell line, with IC₅₀ values ranging from 8.00 to 17.11 µM, and are inactive against the rest of the cell lines. Compounds 3c and 3d showed significant cytotoxicity among the synthesized derivatives. The in silico docking studies revealed compounds 3b and 3d with high binding affinity against the cancer target, transient receptor potential vanilloid 1.     

Terephthalaldehyde: An Effecient Key Precursor for Novel Synthesis of Some Interesting Bis‐thiazoles and Bis‐triazolopyrimidinones

Novel bis‐thiazoles were synthesized in high and efficient yields from the reaction of thiosemicarbazones with halogenated compounds. Also, new bis‐triazolopyrimidines were prepared from the reaction of hydrazonoyl chlorides with bis‐thione derivative. All prepared compounds were fully characterized by spectral methods. The synthesized bis‐compounds will be attractive species for the medicinal researchers to investigate their biological activity.     

Convenient Synthesis of Some Novel Pyridazinone‐Bearing Triazole Moieties

The chemoselective reactions of 2‐(5‐mercapto‐4‐phenyl‐4H‐[1,2,4]triazol‐3‐ylmethyl)‐6‐p‐tolyl‐4,5‐dihydro‐2H‐pyridazin‐3‐one ( 3 ) with different electrophiles were evaluated. Triazole 3 reacted with alkyl halides in the presence of triethylamine in alcohol to give the corresponding S‐substituted derivatives. On the basis of S‐chemoselective reactions of triazole 3 , a series of amino acid 10a – d and dipeptide derivatives 12a – d were prepared via azide coupling of the corresponding hydrazides 9 and 15 with amino acid ester hydrochlorides, respectively. N‐Substituted triazoles 6a – c or 7a – d attached to pyridazin‐3‐one moiety were successfully formed by the reaction of 3 with activated acrylic acid derivatives or with amines. Antibacterial activities of the synthesized derivatives were investigated through correlation with Escherichia coli FabH inhibitory activities using molecular modeling docking software. The antimicrobial activity of synthesized compounds was evaluated, showing best inhibition zone for N‐substituted carboxylic acid 5a and N‐substituted nitrile 5c parallel to the molecular modeling studies.     

A Novel Synthesis of Isoxazole Derivatives

Thenitronesareveryimportantinorganicsynthesis.TheyhavebeenwidelyutilizedasintermediatesfromwhichcomPlexheterocyclicornaturalcompoundsanddrugs"'weresynthesisedsuchasisoxazoline3andoxazine4.However,theconversionofnitronetoisoxazolebythermaldecompositionhasnotbeenreported.Inthispaper,wedevelopanewsyntheticmethodofisoxazolesfromheterocyclicnitronesasfollows:wi.-"'rtXfa.H;b.3,4-O-CH2-o-;c.4-CH3O,d.4-Cl;e.2-Brf.2-Cl,g.3,4-coCH3;h.3-ro2;i.4-so2;j.4-CH3Experiment8lAdriedroundbottomflaskundernit…     

Synthesis of New Spirooxindole‐Fused Isoxazoline/Triazole and Isoxazoline/Isoxazole Derivatives from Three‐Component 1,3‐Dipolar Cycloaddition

A series of diverse heterocycles containing spirooxindole, isoxazoline/triazole, and isoxazole rings has been synthesized via an efficient three‐component reaction of (E )‐2‐(1‐propargyl‐2‐oxoindoline‐3‐ylidene)acetophenones 1 , arylnitrile oxides 2 , and arylazides 3 using Cu(I) as catalyst. The regiochemistry and stereochemistry of cycloadducts 4a and 5a have been confirmed by X‐ray diffraction studies. The heterocycles were screened against Gram‐positive and Gram‐negative bacteria and fungi. Several compounds exhibit moderate to excellent activities comparable to those of established standard drugs.     

A Novel ‘Domino‐Click Approach’ to Unsymmetrical Bis‐1H‐1,2,3‐triazoles

Aryl azides 1 were treated with allenylmagnesium bromide ( 2 ) to generate 1,5‐disubstituted butynyl‐1H‐1,2,3‐triazoles 3 in a domino fashion, which upon Cu^I‐catalyzed 1,3‐dipolar cycloaddition with aryl azides 4 afforded novel bis‐1H‐1,2,3‐triazoles 5 in quantitative yields (Scheme 1 and Table).     

Synthesis and Bioactivity of Novel Bis‐heterocyclic Compounds Containing Pyrazole and Oxadiazoline

Nucleophilic addition of the starting material 3‐aryl‐1‐phenyl‐4‐formylpyrazoles ( 1～3 ) and 4‐substituted aryloxyacetyl hydrazine ( 4a～4e ) afford hydrazone compounds containg pyrazolyl ( 5a～5e, 6a～6e, 7a～7e ) in the ethanol. These adducts were refluxed in Ac₂O and furnished a series of novel bis‐hetero‐cyclic compounds. ( 8a～8e, 9a～9e, 10a～10e ) via cyclic reaction. The structures of all newly synthesized compounds were established by IR, ¹H NMR, MS and elemental analysis. New compounds conducted preliminary tests of antibacterial activities about Fusarium oxyaporium, Verticillium dahliae, Rhizoctonia solani, Pychium aphanidermatum, Alternaria solani, Sclerotinia sclerotiorum. The results showed that the inhibiting rate of the bis‐heterocyclic compounds ( 8a～8e, 9a～9e, 10a～10e ) was higher than the pyrazolyl hydrazones ( 5a～5e, 6a～6e, 7a～7e ) obviously.     

Novel Disubstituted Phenylene‐Linked Bis‐imidazole Derivatives: Facile Synthesis and Optical Properties

Six novel disubstituted phenylene‐linked bis‐imidazole derivatives, 3a – 3f , were prepared by a one‐pot, microwave‐assisted method under solvent‐free conditions, in yields ranging from 61.6 to 85.6%. The new compounds were characterized by ¹H‐ and ¹³C‐NMR, UV/VIS, and fluorescence spectroscopy, and mass spectrometry, as well as by elemental analyses. The influence of substituents and solvents on the optical properties of 3a – 3f was investigated. It was found that there is little influence on absorption and excitation spectra in contrast to emission spectra. Compounds 3a – 3f exhibit strong fluorescence in solution, their fluorescence quantum yields ranging from 0.27 to 0.96.     

Fluorescent Pyrene‐Based Bis‐azole Compounds: Synthesis and Photophysical Analysis

A rational synthetic procedure for the preparation of a series of pyrene‐based neutral and dicationic bis‐azole compounds is reported. The method allows the tailored design of pyrene‐based azoles with different substituents at the nitrogen atoms of the heterocycles, for which the relative conformation of the resulting bis‐azoles can be easily controlled. The bis‐azoliums were used for the preparation of the related diplatinum complexes by reaction with [{Pt(ppy)(μ‐Cl)₂}₂] (ppy=2‐phenylpyridinate). The X‐ray molecular structure of one of the resulting compounds, a diplatinum(II) bis(N‐heterocyclic carbene) complex, is described. Studies on the photophysical properties of all new species are described. The emission of the bis‐azole‐based compounds seems to be independent of their substitution patterns, which basically indicates that physical properties such as solubility, melting point, and viscosity can be fine‐tuned while maintaining the luminescence properties. Finally, the energies associated with the HOMO and LUMO levels suggest that this family provides versatility to match the energy levels of a wide range of host materials, which is important for the preparation of organic light‐emitting devices.     

新型异噁唑啉类化合物的合成及其抗肿瘤活性

以3,4-二氟苯甲醛为起始物,经4步反应合成了关键中间体N-[{3-[3-氟-4-(1-哌嗪基)苯基]4,5-二氢-5-异噁唑}甲基]乙酰胺(4);4与取代苯磺酰氯经亲核取代反应合成了6个新型的异噁唑啉类化合物(6a～6f),其结构经1H NMR和MS表征.采用MTT法对6a～6f进行初步生物活性测试结果表明,部分化合...     

Synthesis of Novel Biphenyltetrazole Derivatives Containing 5‐Methylisoxazole Substituted 1,2,4‐Triazole

An efficient route to synthesize the target compounds was developed. Fifteen new 5‐[4′‐(5‐isoxazol‐4‐aryl‐1,2,4‐triazol‐3‐yl‐sulfanylmethyl)‐biphenyl‐2‐yl]‐tetrazoles derivatives were synthesized. The structures of the new compounds synthesized were confirmed by elemental analyses and spectral data.     

Facile One‐pot,Three‐component Synthesis of Novel Bis‐heterocycles Incorporating 5H‐chromeno[2,3‐b]pyridine‐3‐carbonitrile Derivatives

Novel bis‐chromeno[2,3‐b ]pyridine derivatives were synthesized with good yields by a clean and efficient methodologies involving one‐pot three‐component synthesis of bis‐aldehydes, malononitrile dimer, and dimedone in the presence of piperidine as a catalyst in EtOH. Depending on the length and position of the spacer in the bis‐aldehyde derivatives 1 , the reactions proceeded to give either the bis(2,4‐diamino‐tetrahydro‐5H‐chromeno[2,3‐b ]pyridine‐3‐carbonitriles) 4 or bis(4‐amino‐2,6‐dioxo‐hexahydro‐2H‐chromeno[2,3‐b ]pyridine‐3‐carbonitriles) 5 . All of the new compounds have been characterized by spectral data.     

Convenient Synthesis of Functionalized Bis‐ureidopyrimidinones Based on Thiol‐yne Reaction

The preparation of functionalized bis‐ureidopyrimidinones ( Bis‐UPy ) through the thiol‐yne reaction is described. Various Bis‐UPys with different functional groups were synthesized by using the readily available functionalized alkynes and UPy‐thiol to affirm the simplicity and versatility of the methodology.