Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Mol Divers ; 27(3): 1141-1162, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35737256

RESUMO

Breast cancer is the most common malignancy among women. It is a complex condition with many subtypes based on the hormone receptor. The mammalian target of the rapamycin (mTOR) pathway regulates cell survival, metabolism, growth, and protein synthesis in response to upstream signals in both normal physiological and pathological situations, primarily in cancer. The objective of this study was to screen for a potential target to inhibit the mTOR using a variety of inhibitors derived from Cichorium intybus and to identify the one with the highest binding affinity for the receptor protein. Initially, AutoDock Vina was used to perform structure-based virtual screening, as protein-like interactions are critical in drug development. For the comparative analysis, 110 components of Cichorium intybus were employed and ten FDA-approved anticancer medicines, including everolimus, an mTOR inhibitor. Further, the drug-likeness and ADMET properties were investigated to evaluate the anti-breast cancer activity by applying Lipinski's rule of five to the selected molecules. The promising candidates were then subjected to three replica molecular dynamics simulations run for 100 ns, followed by binding free energy estimation using MM-GBSA. The data were analyzed using root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and protein-ligand interactions to determine the stability of the protein-ligand complex. Based on the results, taraxerone (98) revealed optimum binding affinities with mTOR, followed by stigmasterol (110) and rutin (104), which compared favorably to the control compounds. Subsequently, bioactive compounds derived from Cichorium intybus may serve as lead molecules for developing potent and effective mTOR inhibitors to treat breast cancer.


Assuntos
Neoplasias da Mama , Cichorium intybus , Feminino , Humanos , Sirolimo/uso terapêutico , Inibidores de MTOR , Simulação de Acoplamento Molecular , Ligantes , Simulação de Dinâmica Molecular , Neoplasias da Mama/tratamento farmacológico , Serina-Treonina Quinases TOR
2.
Mol Divers ; 27(5): 2273-2296, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36318405

RESUMO

One of the most common malignancies diagnosed and the leading cause of death for cancer-stricken women globally is breast cancer. The molecular subtype affects therapy options because it is a complex disorder with multiple subtypes. By concentrating on receptor activation, mTOR (mammalian target of rapamycin) can be employed as a therapeutic target. The goal of this work was to screen a number of inhibitors produced from Hibiscus rosa-sinensis for possible target to inhibit the mTOR and to determine which has the greatest affinity for the receptor. Primarily, the ionization states of the chosen compounds were predicted using the ChemAxon web platform, and their pKa values were estimated. Given the significance of interactions between proteins in the development of drugs, structure-based virtual screening was done using AutoDock Vina. Approximately 120 Hibiscus components and ten approved anti-cancer drugs, including the mTOR inhibitor everolimus, were used in the comparative analysis. By using Lipinski's rule of five to the chosen compounds, the ADMET profile and drug-likeness characteristics were further examined to assess the anti-breast cancer activity. The compounds with the highest ranked binding poses were loaded using the SeeSAR tool and the HYDE scoring to give interactive, desolvation, and visual ΔG estimation for ligand binding affinity assessment. Following, the prospective candidates underwent three replicas of 100 ns long molecular dynamics simulations, preceded with MM-GBSA binding free energy calculation. The stability of the protein-ligand complex was determined using root mean square deviation (RMSD), root mean square fluctuation (RMSF), and protein-ligand interactions. The results demonstrated that the best mTOR binding affinities were found for stigmastadienol (107), lupeol (66), and taraxasterol acetate (111), which all performed well in comparison to the control compounds. Thus, bioactive compounds isolated from Hibiscus rosa-sinensis could serve as lead molecules for the creation of potent and effective mTOR inhibitors for the breast cancer therapy.


Assuntos
Neoplasias da Mama , Hibiscus , Rosa , Feminino , Humanos , Simulação de Acoplamento Molecular , Sirolimo/análise , Hibiscus/química , Ligantes , Simulação de Dinâmica Molecular , Flores/química , Serina-Treonina Quinases TOR
3.
Chem Biodivers ; 19(8): e202200144, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35713943

RESUMO

Natural products with semi-synthetic molecules displays higher biological activities, and creates new biological properties for the treatment of diseases. Although, natural products like artemisinin have been used as a traditional medicine over thousands of years, structure and biological properties of many natural products were investigated in the 20th century. Design and synthesis of new biologically active compounds including natural products have very critical roles to find novel drug candidates. Herein, novel thiophene/furan bridge artemisinin derivatives were synthesized by starting from artemisinin. Firstly, benzothiophene derivatives are synthesized, then Steglich esterification reactions give the new artemisinin hybrid molecules with moderate to high yields.


Assuntos
Artemisininas , Produtos Biológicos , Artemisininas/química , Furanos/química , Tiofenos/química
5.
Turk J Chem ; 46(5): 1516-1523, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37529723

RESUMO

A new electrochromic copolymer based on 4,7-di(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole and 3,4-ethylenedioxythiophene was successfully obtained via the electrochemical polymerization method in the medium of electrolyte solution, which consists of 0.1 M tetrabutylammonium hexafluorophosphate and dichloromethane. In order to compare the electrochemical and chemical properties of the copolymer, the benzothiodiazole derivative and 3,4-ethylenedioxythiophene (EDOT) monomers, which are parts of the copolymer, are electrochemically polymerized, separately in the same environment and concentration with the copolymer. Poly(4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole) (P(TBT)) and poly(3,4-ethylenedioxythiophene) (PEDOT) polymers were obtained. Before starting the electrochemical synthesis, the initial oxidation potentials of the monomers that form the copolymer were compared via the cyclic voltammeter method in this solvent electrolyte medium. Then, electrochemical and spectroelectrochemical characterizations of electrochemically synthesized polymers and copolymers were performed. New copolymer shows metallic blue and centaury blue in its neutral and oxidized states, respectively with a low band gap of 1.32 eV. Moreover, the copolymer has a 59% optical contrast and high coloration efficiency (324 cm2C-1) at 585 nm with a switching time of 2.2 s.

6.
Turk J Chem ; 46(4): 1110-1119, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37538771

RESUMO

In this study, a new copolymer, which is a combination of two chemical structure (9,10-di(furan-2-yl)anthracene and 3,4-ethylenedioxythiophene was synthesized via electrochemical synthesis methods in the electrolyte medium of 0.1 M TBAPF6/ACN solution. PEDOT homopolymer was also electrosynthesized for comparator experiments of the polymer formations in the same medium. The characterizations of polymers were achieved with general optical and electrochemical characterization techniques. The corresponding electrochromic copolymer shows blue and lilac color in its neutral and oxidized states, respectively. The copolymer has an optical band gap of 1.65 eV and 24% optical contrast at 500 nm with a high coloration efficiency (170 cm2 /C) and a fast switching time (1.0 s).

7.
Nat Prod Res ; 36(14): 3511-3519, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33416016

RESUMO

A molecular hybridization of natural products is a new concept in drug discovery and having critical roles to design new molecules with improved biological properties. Hybrid molecules display higher biological activities when compared to the parent drugs. In the present study, two natural products (thymol and artemisinin (ART)) are used for the synthesis of new hybrid thymol-artemisinin. After characterization, the cytotoxic activity of ART-thymol was tested against different cancer cell lines and non-cancerous human cell line. ART-Thymol show the cytotoxic effect with EC50 values 70,96µM for HepG2, 97,31µM for LnCap, 6,03µM for Caco-2, 77,98µM for HeLa and 62,28µM for HEK293 cells, respectively. Moreover, ART-Thymol was checked for drug-likeness, and the kinase inhibitory activity. ART-Thymol is investigated by using molecular docking. The results of qPCR was indicated CDK2 and P38 were inhibited by ART-Thymol. These results improved that thymol-artemisinin may be new candidates as an anticancer agents.


Assuntos
Antineoplásicos , Artemisininas , Produtos Biológicos , Antineoplásicos/farmacologia , Artemisininas/farmacologia , Células CACO-2 , Linhagem Celular Tumoral , Células HEK293 , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Timol/farmacologia
8.
Anticancer Agents Med Chem ; 22(2): 362-370, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33719978

RESUMO

BACKGROUND: Marine actinomycetes are among indispensable sources of natural bioactive compounds with unique antimicrobial and anti-cancer activities. OBJECTIVE: Herein, it was aimed to elucidate the bioactive potential of a marine-derived Streptomyces ovatisporus S4702T, isolated previously. METHODS: Streptomyces ovatisporus S4702T was cultured in N-Z Amine broth, and extraction was carried out using different organic solvents. Bioassay-guided purification was followed by chemical characterization using NMR and LC-MS/MS. The compound was then evaluated for its antibacterial, antioxidant and cytotoxic activities. RESULTS: Etyl acetate extracts gave the highest antibacterial activity, and chemical characterization of this extract indicated the formula as C15H29O5N3 and the corresponding possible molecular structure as 4H-chromen-4-one derivative. It was found highly potent against Bacillus subtilis ATCC 6633 (MIC: 0.25 µg ml-1) and Micrococcus luteus ATCC 9341 (MBC: 0.5 µg ml-1). It has no remarkable antioxidant activity, but a higher EC50 value and less cytotoxicity against normal cells. The EC50 values of this chromen derivative were found as 9.68 µg ml-1 for human colon carcinoma, 9.93 µg ml-1 for human prostate adenocarcinoma and 25.5 µg ml-1 for human embryonic kidney cells. CONCLUSION: Overall, the presented 4H-chromen-4-one derivative is a remarkable bioactive compound with potent antibacterial and cytotoxic activity. With its high bioactive potential, it is proposed as a good candidate in medicine.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Cromonas/farmacologia , Streptomyces/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Apoptose/efeitos dos fármacos , Benzotiazóis/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cromonas/química , Cromonas/isolamento & purificação , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Fenetilaminas/antagonistas & inibidores , Relação Estrutura-Atividade , Ácidos Sulfônicos/antagonistas & inibidores
9.
Nat Prod Res ; 36(20): 5228-5234, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34024198

RESUMO

Natural products are used for the treatment of a variety of diseases for many years. Last decades, design and synthesis of novel biologically active hybrid molecules including natural product is gained big importance due to their unique and new biological properties. In the present study, novel artemisinin-benzothiophene derivatives (12 A-F) are synthesised. Initially, benzothiophene derivatives (4 A-4F) are prepared via the Pd-catalyzed coupling reactions and iodocyclisation reactions. Then, Suzuki-Miyaura coupling reactions were used for the formation of intermediates 6 A-6F (between 64% and 91% yields). Finally, the Steglich esterification reaction between intermediate 6 and artesunate formed the artemisinin-benzothiophene hybrids (9 A-9F) in moderate to excellent yields under very mild reaction conditions. When intermediate 6 was reacted with dihydroartemisinin, product 12 A-12F was also obtained with high yields.[Formula: see text].


Assuntos
Artemisininas , Produtos Biológicos , Artesunato , Paládio , Tiofenos
10.
J Mol Model ; 28(1): 17, 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-34962586

RESUMO

Breast cancer is one of the most severe problems, and it is the primary cause of cancer-related death in females worldwide. The adverse effects and therapeutic resistance development are among the most potent clinical issues for potent medications for breast cancer treatment. The eugenol molecules have a significant affinity for breast cancer receptors. The aim of the study has been on the eugenol compounds, which has potent actions on Erα, PR, EGFR, CDK2, mTOR, ERBB2, c-Src, HSP90, and chemokines receptors inhibition. Initially, the drug-likeness property was examined to evaluate the anti-breast cancer activity by applying Lipinski's rule of five on 120 eugenol molecules. Further, structure-based virtual screening was performed via molecular docking, as protein-like interactions play a vital role in drug development. The 3D structure of the receptors has been acquired from the protein data bank and is docked with 87 3D PubChem and ZINC structures of eugenol compounds, and five FDA-approved anti-cancer drugs using AutoDock Vina. Then, the compounds were subjected to three replica molecular dynamic simulations run of 100 ns per system. The results were evaluated using root mean square deviation (RMSD), root mean square fluctuation (RMSF), and protein-ligand interactions to indicate protein-ligand complex stability. The results confirm that Eugenol cinnamaldehyde has the best docking score for breast cancer, followed by Aspirin eugenol ester and 4-Allyl-2-methoxyphenyl cinnamate. From the results obtained from in silico studies, we propose that the selected eugenols can be further investigated and evaluated for further lead optimization and drug development.


Assuntos
Antineoplásicos/química , Eugenol/química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Antineoplásicos/farmacologia , Sítios de Ligação , Neoplasias da Mama , Linhagem Celular Tumoral , Eugenol/farmacologia , Feminino , Humanos , Ligantes , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade
11.
Anticancer Agents Med Chem ; 21(10): 1292-1300, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32951581

RESUMO

BACKGROUND: Indole-based heterocyclic compounds play important roles in pharmaceutical chemistry due to their unexpected biological and pharmacological properties. OBJECTIVE: Herein, we describe novel biological properties (antioxidant, antimicrobial and anti-cancer) of 3- bromo-1-ethyl-1H-indole (BEI) structure. METHODS: BEI was synthesized from 1-Methyl-2-phenylindole and N-bromosuccinimide and was characterized by using 1H and 13C NMR. Cytotoxicity was determined by MTT assay. Apoptosis analysis of BEI was determined by Arthur™ image-based Cytometer. Different methods were applied to assess the antioxidant activity of BEI. Molecular docking studies were conducted to determine the interactions of bonding between GST isozymes and BEI. RESULTS: According to the antioxidant and antimicrobial activity assays, BEI compound showed reduced total antioxidant activity compared to the Trolox standard, whereas it showed moderate antimicrobial activity against Aspergillus niger and Phytophora eryhtrospora. Notably, the BEI compound demonstrated substantial selective cytotoxicity for the first time towards cancer cell lines, and there existed a significant decrease in the percentage of live cells treated with BEI, in comparison to the control ones. Interestingly, BEI exhibited a promising glutathione S-transferase isozymes inhibition. CONCLUSION: The results of this study suggest that BEI seems to be a promising molecule to be used in the design of new anti-cancer agents that provide superiority to present commercial anti-cancer drugs.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Inibidores Enzimáticos/farmacologia , Glutationa Transferase/antagonistas & inibidores , Antibacterianos/síntese química , Antibacterianos/química , Antifúngicos/síntese química , Antifúngicos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Antioxidantes/síntese química , Antioxidantes/química , Apoptose/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Benzotiazóis/antagonistas & inibidores , Compostos de Bifenilo/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Fungos/efeitos dos fármacos , Glutationa Transferase/metabolismo , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Picratos/antagonistas & inibidores , Relação Estrutura-Atividade , Ácidos Sulfônicos/antagonistas & inibidores
12.
Int Immunopharmacol ; 90: 107232, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33290969

RESUMO

Coronavirus, known as the coronavirus pandemic, is continuing its spread across the world, with over 42 million confirmed cases in 189 countries and more than 1.15 million deaths. Although, scientists focus on the finding novel drugs and vaccine for SARS-CoV-2, there is no certain treatment for it. Antiviral drugs such as; oseltamivir, favipiravir, umifenovir, lopinavir, remdesivir, hydroxychloroquine, chloroquine, azithromycin, ascorbic acid, corticosteroids, are mostly used for patients. They prevent cytokine storm that is the main reason of deaths related to SARS-CoV-2. In addition, anti-inflammatory agents have critical roles to inhibit the lung injury and multisystem organ dysfunction. The combination with anti-viral drugs with other drugs displays high synergistic effects. In the present study, the drugs used for Covid-19 are analyzed and compare the efficiency for the Covid-19 patients from the different continents including USA, South Korea, Italy, Spain, Germany, Russia, Brazil, Turkey, and China. Nowadays, all countries tried to find vaccine and new drug candidates for SARS-CoV-2, but anti-viral drugs may be the best candidates for the treatment of Covid-19 before finding novel anti-Covid drug.


Assuntos
Antivirais/uso terapêutico , Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Antivirais/química , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/prevenção & controle , Humanos , Resultado do Tratamento
13.
Mater Sci Eng C Mater Biol Appl ; 90: 454-460, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29853112

RESUMO

Herein, (3-aminopropyl)triethoxysilane functionalized cerium (IV) oxide (CeO2-NH2) supported Pd nanoparticles were synthesized. The nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and High-resolution transmission electron microscopy (HRTEM). The Pd@CeO2-NH2 showed better electrocatalytic response to the reduction of H2O2 than CeO2-NH2. The fabricated sensor exhibited two linear responses to the reduction of H2O2. The first one was from 0.001 to 3.276 mM with 0.47 µM of a limit of detection (LOD) (S/N = 3) and excellent sensitivity of 440.72 µA mM-1 cm-2 and the second one was from 3.276 to 17.500 mM with the sensitivity of 852.65 µA mM-1 cm-2 in the optimum conductions. Also, the sensor exhibited 91% of electrocatalytic activity toward H2O2 after having been used for 30 days and the reproducibility was also satisfactory. The sensor response to H2O2 was not affected by ascorbic acid, fructose, glycine, dopamine, arginine, mannose, glucose, uric acid, Mg+2, Ca+2, and phenylalanine at the studied potential. Also, the fabricated sensor was used to determine H2O2 in milk samples. The results show that the constructed sensor can be a promising devise for the determination of H2O2 in real samples.


Assuntos
Peróxido de Hidrogênio/química , Nanocompostos/química , Carbono/química , Técnicas Eletroquímicas/métodos , Grafite/química , Nanopartículas Metálicas/química
14.
Environ Sci Pollut Res Int ; 23(12): 12343-51, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26979315

RESUMO

Acetylcholinesterase (AChE) biosensor based on conducting poly([2,2̍';5̍' 2″]-terthiophene-3̍-carbaldehyde) (PTT) modified glassy carbon electrode (GCE) was constructed. AChE was immobilized on PTT film surface through the covalent bond between aldehyde and amino groups. The properties of PTT modified GCE were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The biosensor showed an oxidation peak at +0.83 V related to the oxidation of thiocholine, hydrolysis product of acetylthiocholine iodide (ATCI), catalyzed by AChE. The optimum current response of the biosensor was observed at pH 7.5-8.0, 40 °C and 120 U/cm(2) of AChE concentration. The biosensor showed a high sensitivity (183.19 µA/mM), a linear range from 0.015 to 1.644 mM, and a good reproducibility with 1.7 % of relative standard deviation (RSD). The biosensor showed a good stability. The interference of glycin, ascorbic acid, histidine, uric acid, dopamine, and arginine on the biosensor response was studied. An important analytical response from these inteferents that overlaps the biosensor response was not observed. The inhibition rate of malathion as a model pesticide was proportional to its concentrations from 9.99 to 99.01 nM. The detection limit was 4.08 nM.


Assuntos
Acetilcolinesterase/metabolismo , Malation/análise , Praguicidas/análise , Técnicas Biossensoriais/métodos , Carbono/química , Espectroscopia Dielétrica , Eletrodos , Limite de Detecção , Malation/metabolismo , Praguicidas/metabolismo , Reprodutibilidade dos Testes
15.
Int J Biol Macromol ; 79: 262-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25934105

RESUMO

In the study, the electrochemical behavior of glucose oxidase (GOx) immobilized on poly([2,2';5',2″]-terthiophene-3'-carbaldehyde) (poly(TTP)) modified glassy carbon electrode (GCE) was investigated. The biosensor (poly(TTP)/GOx/GCE) showed a pair of redox peaks in 0.1 M phosphate buffer (pH 7.4) solution in the absence of oxygen the co-substrate of GOx. In here, Poly(TTP)/GOx/GCE biosensor acts as the co-substrate instead of oxygen. Upon the addition of glucose, the reduction and oxidation peak currents increased until the active site of GOx was fully saturated with glucose. The apparent m was estimated 26.13 mM from Lineweaver-Burk graph. The biosensor displayed a good stability and bioactivity. The biosensor showed a high sensitivity (56.1 nA/mM), a linear range (from 0.5 to 20.15 mM), and a good reproducibility with 3.6% of relative standard deviation. In addition, the interference currents of glycin, ascorbic acid, histidine, uric acid, dopamine, arginine, and fructose on GOx biosensor were investigated. All that substances exhibited an interference current under 10%. It was not shown a marked difference between GOx biosensor and spectrophotometric measurement of glucose in serum examples. UV-visible spectroscopy and scanning electron microscopy (SEM) experiments of the biosensor were also performed.


Assuntos
Técnicas Biossensoriais/métodos , Glicemia/análise , Enzimas Imobilizadas/química , Glucose Oxidase/química , Aldeídos/química , Eletrodos , Humanos , Cinética , Oxirredução , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tiofenos/química
16.
J Org Chem ; 76(22): 9379-90, 2011 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-21992574

RESUMO

Synthesis of pyrazoles via electrophilic cyclization of α,ß-alkynic hydrazones by copper(I) iodide is described. When treated with copper(I) iodide in the presence of triethylamine in refluxing acetonitrile, α,ß-alkynic hydrazones, prepared readily from hydrazines and propargyl aldehydes and ketones, undergo electrophilic cyclization to afford pyrazole derivatives in good to excellent yields. The reaction appears to be general for a variety of α,ß-alkynic hydrazones and tolerates the presence of aliphatic, aromatic, and ferrocenyl moieties with electron-withdrawing and electron-donating substituents.


Assuntos
Cobre/química , Hidrazinas/química , Iodetos/química , Pirazóis/síntese química , Catálise , Ciclização , Elétrons , Estrutura Molecular , Pirazóis/química , Estereoisomerismo
17.
J Org Chem ; 76(16): 6726-42, 2011 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-21739980

RESUMO

Electrophilic cyclizations of α,ß-alkynic hydrazones by molecular iodine were investigated for the synthesis of 4-iodopyrazoles. α,ß-Alkynic hydrazones were readily prepared by the reactions of hydrazines with propargyl aldehydes and ketones. When treated with molecular iodine in the presence of sodium bicarbonate, α,ß-alkynic hydrazones underwent electrophilic cyclization to afford 4-iodopyrazoles in good to high yields. Iodocyclization was general for a wide range of α,ß-alkynic hydrazones and tolerated the presence of aliphatic, aromatic, heteroaromatic, and ferrocenyl moieties with electron-withdrawing and electron-donating substituents.


Assuntos
Hidrazonas/química , Iodo/química , Pirazóis/síntese química , Ciclização , Elétrons , Compostos Ferrosos/química , Estrutura Molecular , Pirazóis/química
18.
J Org Chem ; 75(21): 7381-7, 2010 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-20936802

RESUMO

Dihydrobenzisoxazoles are readily prepared in good yields by the [3 + 2] cycloaddition of oxaziridines and arynes. The reaction involves an unusual cleavage of the C-O bond of the oxaziridine and tolerates a variety of substituents on the oxaziridine and the o-(trimethylsilyl)aryl triflate to form aryl-, heteroaryl-, alkyl-, and naphthyl-substituted dihydrobenzisoxazoles. The resulting halogen-substituted dihydrobenzisoxazoles are readily elaborated to more complex products using palladium-catalyzed crossing-coupling processes.


Assuntos
Hidrocarbonetos Aromáticos/química , Isoxazóis/química , Isoxazóis/síntese química , Oxazinas/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...