RESUMO
A catalytic manifold that enables photoredox cross-electrophile coupling of alkyl bromides with DNA-tagged aryl iodides in aqueous solution is presented. This metallaphotoredox transformation was aided by the identification of a new pyridyl bis(carboxamidine) ligand, which proved critical to the nickel catalytic cycle. The described C(sp2)-C(sp3) coupling tolerates a wide range of both DNA-tagged aryl iodides as well as alkyl bromides. Importantly, this reaction was optimized for parallel synthesis, which is a paramount prerequisite for the preparation of combinatorial libraries, by using a 96-well plate-compatible blue LED array as the light source. Therefore, this mild and DNA-compatible transformation is well positioned for the construction of DNA-encoded libraries.
Assuntos
Alcanos/química , Brometos/química , DNA/química , Hidrocarbonetos Aromáticos/química , Iodetos/química , Alcanos/síntese química , Alquilação , Brometos/síntese química , Catálise , Técnicas de Química Combinatória , DNA/síntese química , Hidrocarbonetos Aromáticos/síntese química , Iodetos/síntese química , Ligantes , Níquel/química , Oxirredução , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/químicaRESUMO
A photoassisted Ni-catalyzed reductive cross-coupling between tosyl-protected alkyl aziridines and commercially available (hetero)aryl iodides is reported. This mild and modular method proceeds in the absence of stoichiometric heterogeneous reductants and uses an inexpensive organic photocatalyst to access medicinally valuable ß-phenethylamine derivatives. Unprecedented reactivity was achieved with the activation of cyclic aziridines. Mechanistic studies suggest that the regioselectivity and reactivity observed under these conditions are a result of nucleophilic iodide ring opening of the aziridine to generate an iodoamine as the active electrophile. This strategy also enables cross-coupling with Boc-protected aziridines.
Assuntos
Aziridinas/síntese química , Iodetos/síntese química , Fenetilaminas/química , Catálise , Humanos , Estrutura Molecular , EstereoisomerismoRESUMO
A series of novel quinoline and quinolinium iodide derivatives were designed and synthesized to discover potential anticancer and antibacterial agents. With regard to anticancer properties, inâ vitro cytotoxicities against three human cancer cell lines (A-549, HeLa and SGC-7901) were evaluated. The antibacterial properties against two strains, Escherichia coli (ATCC 29213) and Staphylococcus aureus (ATCC 8739), along with minimum inhibitory concentration (MIC) values were evaluated. The target alkyliodine substituted compounds exhibited significant antitumor and antibacterial activity, of which compound 8-((4-(benzyloxy)phenyl)amino)-7-(ethoxycarbonyl)-5-propyl-[1,3]dioxolo[4,5-g]quinolin-5-ium (12) was found to be the most potent derivative with IC50 values of 4.45±0.88, 4.74±0.42, 14.54±1.96, and 32.12±3.66 against A-549, HeLa, SGC-7901, and L-02 cells, respectively, stronger than the positive controls 5-FU and MTX. Furthermore, compound 12 had the most potent bacterial inhibitory activity. The MIC of this compound against both E. coli and S. aureus was 3.125â nmol â mL-1 , which was smaller than that against the reference agents amoxicillin and ciprofloxacin.
Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Desenho de Fármacos , Iodetos/farmacologia , Quinolinas/farmacologia , Compostos de Quinolínio/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/efeitos dos fármacos , Humanos , Iodetos/síntese química , Iodetos/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Quinolinas/síntese química , Quinolinas/química , Compostos de Quinolínio/síntese química , Compostos de Quinolínio/química , Sais/síntese química , Sais/química , Sais/farmacologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
Steryl glycosides are prevalent in nature and have unique biological activities dictated by sterol structure, sugar composition, and the stereochemical attachment of the aglycone. A single configurational switch can have profound biological consequences meriting the systematic study of structure and function relationships. Steryl congeners of N-acetyl neuraminic acid (NANA) impact neurobiological processes and may also mediate host/microbe interactions. In order to study these processes, a platform for the synthesis of ß-steryl sialosides has been established. Promoter-free glycosidations using a novel α-linked sialyl iodide donor efficiently provide unique amphiphilic sialoglycoconjugates for examining bioactivities in various systems.
Assuntos
Iodetos/síntese química , Ácidos Siálicos/química , Glicosídeos/química , Iodetos/química , Estrutura Molecular , Esteróis/químicaRESUMO
In this study, an N-heterocyclic carbene (NHC)-based metallosurfactant (MS), NHC-PdMS, was synthesized, where Pd(II) was bound to the NHC framework via a robust Pd-carbene bond with NEt3 as a co-ligand. Surface tension measurements revealed that the critical micelle concentration (CMC) of NHC-PdMS (1.8×10-4 M) was one order of magnitude lower than that of its MS precursor (imidazolium bromide). Coordination of the MS precursor and NEt3 to Pd(II) also influenced micelle size; the hydrodynamic diameters of NHC-PdMS and the MS precursor were observed to be 25.8±5.6 nm and 2.5±0.3 nm, respectively. Furthermore, small angle X-ray scattering measurements indicated that NHC-PdMS exhibited liquid crystalline behavior above 26 wt%, with a spacing ratio of 1:2:3 for the first, second, and third Bragg peaks. To understand the role of the reactive interface, NHC-PdMS was also applied to aqueous catalytic reactions. Owing to its low CMC value, a catalytic amount of NHC-PdMS (3 mol%) provided the reactive interface, which facilitated the aqueous Mizoroki-Heck reaction of various aryl iodides and styrene in good yields (72-95%). These results suggest that MS formation results in a drastic change in selfassembling properties, which are important for the development of highly reactive chemical interfaces in water.
Assuntos
Compostos Heterocíclicos/química , Compostos Heterocíclicos/síntese química , Metano/análogos & derivados , Paládio/química , Tensoativos/química , Tensoativos/síntese química , Água/química , Brometos/química , Catálise , Cristalografia por Raios X , Imidazóis/química , Iodetos/síntese química , Ligantes , Cristais Líquidos/química , Metano/síntese química , Metano/química , Micelas , Conformação Molecular , Fenômenos de Química Orgânica , Espalhamento de Radiação , Estireno/síntese química , Tensão SuperficialRESUMO
In this study, the authors reported the first synthesis process of silver iodide (AgI) nanoparticles (NPs) by pulsed laser ablation of the AgI target in deionised distilled water. The optical and structural properties of AgI NPs were investigated by using UV-vis absorption, X-ray diffraction, scanning electron microscope (SEM), energy dispersive X-ray, Fourier transform infrared spectroscopy, and transmission electron microscope (TEM). The optical data showed the presence of plasmon peak at 434â nm and the optical bandgap was found to be 2.6â eV at room temperature. SEM results confirm the agglomeration and aggregation of synthesised AgI NPs. TEM investigation showed that AgI NPs have a spherical shape and the average particle size was around 20â nm. The particle size distribution was the Gaussian type. The results showed that the synthesised AgI NPs have antibacterial activities against both bacterial strains and the activities were more potent against gram-negative bacteria.
Assuntos
Antibacterianos/síntese química , Iodetos/síntese química , Terapia a Laser/métodos , Nanopartículas Metálicas , Compostos de Prata/síntese química , Antibacterianos/química , Iodetos/química , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/química , Compostos de Prata/química , Soluções , Staphylococcus aureus/efeitos dos fármacosRESUMO
ZnFe2O4/AgI composites were first prepared successfully with a hydrothermal method, and ZnFe2O4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe2O4/AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe2O4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe2O4/AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80â¯min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40â¯min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe2O4/AgI composites. In addition, H2O2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe2O4/AgI composites are a promising candidate for the treatment of wastewater.
Assuntos
Antibacterianos/química , Desinfecção/métodos , Compostos Férricos/química , Iodetos/química , Nanopartículas/química , Fotólise , Compostos de Prata/química , Zinco/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Catálise , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Recuperação e Remediação Ambiental/métodos , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Compostos Férricos/síntese química , Compostos Férricos/farmacologia , Humanos , Iodetos/síntese química , Iodetos/farmacologia , Nanopartículas/ultraestrutura , Rodaminas/química , Rodaminas/isolamento & purificação , Compostos de Prata/síntese química , Compostos de Prata/farmacologia , Zinco/farmacologiaRESUMO
We report Pd(II)-catalyzed ß-C(sp3)-H (hetero)arylation of a variety of ketones using a commercially available 2,2-dimethyl aminooxyacetic acid auxiliary. Facile installation and removal of the auxiliary as well as its superior scope for both ketones and (hetero)aryl iodides overcome the significant limitations of the previously reported ß-C(sp3)-H arylation of ketones. The ready availability of ketones renders this reaction a broadly useful method for alkyl-(hetero)aryl coupling involving both primary and secondary alkyls.
Assuntos
Hidrocarbonetos Aromáticos/química , Iodetos/química , Cetonas/química , Paládio/química , Alquilação , Ácido Amino-Oxiacético/síntese química , Ácido Amino-Oxiacético/química , Catálise , Hidrocarbonetos Aromáticos/síntese química , Iodetos/síntese química , Cetonas/síntese químicaRESUMO
The development of a general catalytic system for the palladium-catalyzed carbocyclization of unactivated alkyl bromides with alkenes is described. This approach uses a commercially available bisphosphine ligand and avoids the use of carbon monoxide atmosphere present in prior studies involving alkyl iodides. Detailed mechanistic studies of the transformation are performed, which are consistent with auto-tandem catalysis involving atom-transfer radical cyclization followed by catalytic dehydrohalogenation. These studies also suggest that reactions involving alkyl iodides may proceed through a metal-initiated, rather than metal-catalyzed, radical chain process.
Assuntos
Alcenos/química , Brometos/química , Paládio/química , Alcenos/síntese química , Alquilação , Brometos/síntese química , Catálise , Ciclização , Halogenação , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/química , Iodetos/síntese química , Iodetos/química , LigantesRESUMO
A 3,4-disubstituted pyrrolidine ring was effectively cyclized through SmI2-mediated reductive coupling between allyl chloride and an α,ß-unsaturated ester, although little has been reported about SmI2-promoted C-C bond formation of an allyl chloride with an α,ß-unsaturated ester. Selection of either the 3,4-cis- or 3,4-trans-selective cyclization can be accomplished simply by changing the additives from NiI2 to HMPA during reductive cyclization conducted in H2O-THF. Total synthesis of (-)-kainic acid and (+)-allo-kainic acid, which are pyrrolidine alkaloids used in neuroscience and neuropharmacology as useful molecular probes, was successfully achieved by using the stereo-complementary ring closure reactions promoted by SmI2 for the construction of the 2,3,4-trisubsituted pyrrolidine scaffold of kainoids.
Assuntos
Compostos Alílicos/química , Iodetos/química , Ácido Caínico/análogos & derivados , Ácido Caínico/síntese química , Samário/química , Compostos Alílicos/síntese química , Ciclização , Ésteres/síntese química , Ésteres/química , Iodetos/síntese química , OxirreduçãoRESUMO
We have developed a method for palladium-catalyzed, pyrazole-directed sp3 C-H bond arylation by aryl iodides. The reaction employs a Pd(OAc)2 catalyst at 5-10â mol % loading and silver(I) oxide as a halide-removal agent, and it proceeds in acetic acid or acetic acid/hexafluoroisopropanol solvent. Ozonolysis of the pyrazole moiety affords pharmaceutically important ß-phenethylamines.
Assuntos
Paládio/química , Fenetilaminas/síntese química , Pirazóis/química , Catálise , Iodetos/síntese química , Iodetos/química , Óxidos/química , Fenetilaminas/química , Pirazóis/síntese química , Compostos de Prata/químicaRESUMO
The haem protein lactoperoxidase (LPO) is an important component of the anti-microbial immune defence in external secretions and is also applied as preservative in food, oral care and cosmetic products. Upon oxidation of SCN(-) and I(-) by the LPO-hydrogen peroxide system, oxidised species are formed with bacteriostatic and/or bactericidal activity. Here we describe the formation of the inter(pseudo)halogen cyanogen iodide (ICN) by LPO. This product is formed when both, thiocyanate and iodide, are present together in the reaction mixture. Using (13)C nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry we could identify this inter(pseudo)halogen after applying iodide in slight excess over thiocyanate. The formation of ICN is based on the reaction of oxidised iodine species with thiocyanate. Further, we could demonstrate that ICN is also formed by the related haem enzyme myeloperoxidase and, in lower amounts, in the enzyme-free system. As I(-) is not competitive for SCN(-) under physiologically relevant conditions, the formation of ICN is not expected in secretions but may be relevant for LPO-containing products.
Assuntos
Iodetos/síntese química , Lactoperoxidase/química , Compostos de Nitrogênio/síntese química , Animais , Biocatálise , Bovinos , Peróxido de Hidrogênio/química , Leite/enzimologia , Oxirredução , Peroxidase/químicaRESUMO
A primary-alkyl-substituted selenenyl iodide was successfully synthesized through oxidative iodination of a selenol with N-iodosuccinimide by taking advantage of a cavity-shaped steric protection group. The selenenyl iodide exhibited high thermal stability and remained unchanged upon heating at 100 °C for 3 h in [D8]toluene. The selenenyl iodide was reduced to the corresponding selenol by treatment with dithiothreitol. Hydrolysis of the selenenyl iodide under alkaline conditions afforded the corresponding selenenic acid almost quantitatively, corroborating the chemical validity of the recent proposal that hydrolysis of a selenenyl iodide to a selenenic acid is potentially involved in the catalytic mechanism of an iodothyronine deiodinase.
Assuntos
Ácidos Carboxílicos/metabolismo , Iodetos/síntese química , Compostos Organosselênicos/metabolismo , Compostos de Selênio/química , Succinimidas/química , Catálise , Halogenação , Hidrólise , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , OxirreduçãoRESUMO
Many 1,3-azoles and thiophenes are directly cyclopropylated in the presence of a simple palladium catalyst. The relative configuration on the three-membered rings is retained in the products. Thus, the cyclopropyl-halide bond undergoes concerted oxidative addition to palladium(0) and cyclopropyl radicals are not involved in the productive pathway.
Assuntos
Ciclopropanos/química , Compostos Heterocíclicos/química , Paládio/química , Azóis/síntese química , Azóis/química , Benzoxazóis/síntese química , Benzoxazóis/química , Catálise , Ciclopropanos/síntese química , Compostos Heterocíclicos/síntese química , Iodetos/síntese química , Iodetos/química , Tiofenos/síntese química , Tiofenos/químicaRESUMO
A combination of dimethylzinc, perfluoroalkyl iodide, and LiCl afforded a new type of perfluoroalkyl (RF ) zinc ate complex. These complexes show much greater thermal stability than conventional perfluorinated metal species, such as RF -lithium species and Grignard reagents, and they can be used at room temperature or higher. The results of DFT calculations on the origin of the enhanced stability are reported and the synthetic utility of RF -zincate complexes is demonstrated.
Assuntos
Complexos de Coordenação/química , Fluorocarbonos/química , Compostos Organometálicos/química , Zinco/química , Complexos de Coordenação/síntese química , Fluorocarbonos/síntese química , Iodetos/síntese química , Iodetos/química , Compostos Organometálicos/síntese químicaRESUMO
The scope of MgI2 as a valuable tool for quantitative and mild chemoselective cleavage of protecting groups is described here. This novel synthetic approach expands the use of protecting groups, widens the concept of orthogonality in synthetic processes, and offers a facile opportunity to release compounds from solid supports.
Assuntos
Iodetos/química , Compostos de Magnésio/química , Técnicas de Síntese em Fase Sólida/métodos , Aminoácidos/síntese química , Aminoácidos/química , Esterificação , Ésteres/química , Química Verde , Iodetos/síntese química , Compostos de Magnésio/síntese química , SolventesRESUMO
In this paper, we report the preparation of Natrolite zeolite supported copper nanoparticles as a heterogeneous catalyst for 1,3-diploar cycloaddition and synthesis aryl nitriles from aryl iodides under ligand-free conditions. The catalyst was characterized using XRD, SEM, TEM, EDS and TG-DTA. The experimental procedure is simple, the products are formed in high yields and the catalyst can be recycled and reused several times without any significant loss of catalytic activity.
Assuntos
Cobre/química , Iodetos/química , Nanopartículas/química , Nitrilas/síntese química , Silicatos/química , Triazóis/síntese química , Zeolitas/química , Catálise , Reação de Cicloadição , Química Verde , Iodetos/síntese química , Ligantes , Nanopartículas/ultraestrutura , Nitrilas/química , Triazóis/químicaRESUMO
We report here a pressure-driven metathesis reaction where Ag-exchanged natrolite (Ag16Al16Si24O80·16H2O, Ag-NAT) is pressurized in an aqueous CsI solution, resulting in the exchange of Ag(+) by Cs(+) in the natrolite framework forming Cs16Al16Si24O80·16H2O (Cs-NAT-I) and, above 0.5 GPa, its high-pressure polymorph (Cs-NAT-II). During the initial cation exchange, the precipitation of AgI occurs. Additional pressure and heat at 2 GPa and 160 °C transforms Cs-NAT-II to a pollucite-related, highly dense, and water-free triclinic phase with nominal composition CsAlSi2O6. At ambient temperature after pressure release, the Cs remains sequestered in a now monoclinic pollucite phase at close to 40 wt % and a favorably low Cs leaching rate under back-exchange conditions. This process thus efficiently combines the pressure-driven separation of Cs and I at ambient temperature with the subsequent sequestration of Cs under moderate pressures and temperatures in its preferred waste form suitable for long-term storage at ambient conditions. The zeolite pollucite CsAlSi2O6·H2O has been identified as a potential host material for nuclear waste remediation of anthropogenic (137)Cs due to its chemical and thermal stability, low leaching rate, and the large amount of Cs it can contain. The new water-free pollucite phase we characterize during our process will not display radiolysis of water during longterm storage while maintaining the Cs content and low leaching rate.
Assuntos
Césio/isolamento & purificação , Troca Iônica , Silicatos/química , Prata/química , Zeolitas/química , Cátions , Césio/química , Iodetos/síntese química , Pressão , Resíduos Radioativos , Compostos de Prata/síntese química , Temperatura , Gerenciamento de Resíduos , Água/químicaRESUMO
In this paper, we report the successful growth of complex compound of zinc iodide with thiocarbamide by slow evaporation method. The single crystal XRD study reveals that the crystal belongs to monoclinic system with centrosymmetric space group and powder XRD analysis shows that the perfect crystalline nature of the crystal. The presence of functional group and element were confirmed from FT-IR and EDAX analysis. Optical absorbance of the grown crystal was studied by UV-Vis spectrophotometer. The optical constants were calculated from the optical absorbance data such as refractive index (n), extinction coefficient (K) and reflectance (R). The optical band gap (Eg) of thiocarbamide zinc iodide crystal is 4.22 eV. The magnetic properties of grown crystal have been determined by Vibrating Sample Magnetometry (VSM). Room temperature magnetization revealed a ferromagnetic behaviour for the grown crystal. The antibacterial and antifungal activities of the title compound were performed by well diffusion method and MIC method against the standard bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and against fungus like Aspergillus niger, Rhizopus sps and Penicillium sps. Thermal behaviour of the crystal has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA).
Assuntos
Anti-Infecciosos/farmacologia , Iodetos/síntese química , Iodetos/farmacologia , Imãs , Bases de Schiff/síntese química , Bases de Schiff/farmacologia , Temperatura , Compostos de Zinco/síntese química , Compostos de Zinco/farmacologia , Bactérias/efeitos dos fármacos , Fungos/efeitos dos fármacos , Iodetos/química , Ligantes , Testes de Sensibilidade Microbiana , Fenômenos Ópticos , Pós , Bases de Schiff/química , Espectrometria por Raios X , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Compostos de Zinco/químicaRESUMO
A unique decelerated hydrolytic procedure is developed and reported here for the preparation of ultrasmall nanoparticles (NPs) of PVP-coated BiOI with a narrow size distribution, i.e., 2.8 ± 0.5 nm. The crystal structure of this compound is determined by X-ray powder diffraction using the bulk materials. The stability, cytotoxicity, and potential use of the PVP-coated ultrasmall BiOI NPs as a CT contrast agent are investigated. Because of the combined X-ray attenuation effect of bismuth and iodine, such NPs exhibit a CT value that is among the best of those of the inorganic nanoparticle-based CT contrast agents reported in the literature.