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1.
J Org Chem ; 85(2): 622-632, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31799847

RESUMO

An efficient Pd-catalyzed arylation of alkylpyridine based on the pyridinium activation strategy has been developed for synthesis of mixed aryl alkylpyridines. It was found that (1) the N-methyl group in the pyridinium salts acted as a transient activator and could be automatically departed after the reaction, (2) CuBr was an indispensable additive for achieving the C6-selective arylation, (3) the α-branched alkyl chain on the alkylpyridine greatly increased the yield of the product. Deuterium labelling experiment revealed that in the case of the α-branched alkylpyridine, the presence of CuBr completely inhibited the H/D exchange at the benzylic position and thus enabled the selective arylation at the C6 position. This protocol demonstrates a broad substrate scope, and with respect to both the aryl iodides and the α-branched alkylpyridine, the desired mixed aryl alkylpyridines were obtained in generally good to excellent yields.

2.
J Org Chem ; 84(14): 9151-9160, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31273988

RESUMO

A selective catalytic system for the dehydrogenation of primary alcohols to carboxylic acids using a facial ruthenium complex generated in situ from the [Ru(COD)Cl2]n and a hybrid N-heterocyclic carbene (NHC)-phosphine-phosphine ligand (CPP) has been first reported. The facial coordination model was unveiled by NMR analysis of the reaction mixture. Such a fac-ruthenium catalyst system exhibited high catalytic activity and stability, and a high turnover number of 20 000 could be achieved with catalyst loading as low as 0.002 mol %. The exceedingly high catalyst stability was tentatively attributed to both the anchoring role of NHC and the hemi-lability of phosphines. The catalytic system also features a wide substrate scope. In particular, the facial coordination of CPP ligands was found to be beneficial for sterically hindered alcohols, and ortho-substituted benzylic alcohols and bulky adamantanyl methanol as well as cholesterol were all found to be viable dehydrogenation substrates.

3.
J Org Chem ; 84(4): 2158-2168, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30676029

RESUMO

Herein, an efficient and green method for the selective synthesis of tertiary amines has been developed that involves iridium-catalyzed alkylation of various primary amines with aromatic or aliphatic alcohols. Notably, the catalytic protocol enables this transformation in the absence of additional base and solvent. Furthermore, the alkylation of nitrobenzene with primary alcohol to tertiary amine has also been achieved by the same catalytic system. Deuterium-labeling experiments and a series of control experiments were conducted, and the results suggested that an intermolecular borrowing hydrogen pathway might exist in the alkylation process.

4.
J Org Chem ; 83(8): 4441-4454, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29595260

RESUMO

The first Pd-catalyzed multicomponent reaction of aryl iodides, alkenyl bromides, and strained alkenes has been developed, which allowed us to synthesize a variety of multisubsituted olefins in yields of 45-96% with excellent stereoselectivity. The configuration of the product was controlled by the configuration of the alkenyl bromides. Moreover, this practical methodology employing readily available substrates was found to be tolerant to a wide range of functional groups. Fifty six examples of highly stereoselective tri- or tetrasubstituted olefins have been successfully synthesized via this methodology. Most of the synthesized tetrasubstituted olefins are good aggregation-induced emission (AIE) luminogens.

5.
J Org Chem ; 82(5): 2523-2534, 2017 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-28165232

RESUMO

A simple and efficient strategy for the synthesis of 1-propenylnaphthols from readily accessible 3-arylallylnaphthyl ethers has been developed. By using K2CO3 as base and 2-methoxyethanol as solvent, direct access to a wide range of 1-propenylnaphthols can be achieved in generally good yield (up to 99%) with high stereoselectivity toward the Z isomer. The control experiments indicate that the reaction proceeds through a sequential Claisen rearrangement/isomerization process. Furthermore, starting from the same material, the highly valuable 3-arylnaphtho[2,1-b]furans can be obtained in N,N-dimethylformamide and in the presence of Ag2O as the oxidant via a one-pot sequential Claisen rearrangement/isomerization/cyclization reaction. Mechanistic studies confirm that 1-propenylnaphthols are the key intermediates to form the 3-arylnaphtho[2,1-b]furans. In addition, these two operationally simple and practical protocols could be scaled up to a gram level.

6.
Chem Commun (Camb) ; 50(45): 6023-6, 2014 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-24770847

RESUMO

A catalyst composed of [Pd(η(3)-C3H5)Cl]2 and N,N,N',N'-tetra(diphenylphosphinomethyl)pyridine-2,6-diamine (L) was found to be effective for one-pot synthesis of 2-substituted benzo[b]furans from 2-halophenols and alkynes. For 2-bromo-3-hydroxypyridine, the catalyst loading could be as low as 1 ppm and the turnover number (TON) was up to 870,000.


Assuntos
Alquinos/química , Benzofuranos/síntese química , Compostos Organometálicos/química , Paládio/química , Fenóis/química , Fosfinas/química , Catálise
7.
Artigo em Inglês | MEDLINE | ID: mdl-22484254

RESUMO

The interactions of rhodium complex RhCl(CO)(TPPTS)(2) [TPPTS=P(m-C(6)H(4)SO(3)Na)(3)] with cationic, nonionic, and anionic surfactants have been investigated by UV-vis, fluorescence and (1)H NMR measurements. The presence of four different species of RhCl(CO)(TPPTS)(2) in cationic cetyltrimethylammonium (CTAB) solution has been demonstrated: free rhodium complex, rhodium complex bound to CTAB monomer, rhodium complex bound to CTAB premicelles, rhodium complex bound to CTAB micelles. The spectroscopy data show that RhCl(CO)(TPPTS)(2) can adsorb on the interface of cationic CTAB micelles by strong electrostatic attraction, weakly bind to the nonionic polyoxyethylene (20) sorbitan monolaurate (Tween 20) micelles by hydrophobic interaction, and does not interact with anion sodium dodecyl sulfate (SDS) micelles due to the strong electrostatic repulsion.


Assuntos
Complexos de Coordenação/química , Ródio/química , Tensoativos/química , Cetrimônio , Compostos de Cetrimônio/química , Espectroscopia de Ressonância Magnética , Micelas , Polissorbatos/química , Dodecilsulfato de Sódio/química , Solubilidade , Espectrometria de Fluorescência , Água/química
8.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 6): o1226, 2009 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-21583094

RESUMO

In the title compound, C(23)H(19)NO(3), there is an intra-molecular O-H⋯N hydrogen bond, which forms a six-membered ring, and inter-molecular O-H⋯O hydrogen bonds stabilize the crystal structure.

10.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 2): m429, 2008 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-21201372

RESUMO

In the title compound, [RuCl(2)(C(7)H(8))(C(21)H(21)O(3)P)], the Ru(II) atom possesses a pseudo-octa-hedral geometry and the metrical parameters around the metallic core compare well with those of similar three-legged-piano-stool complexes.

11.
Acta Crystallogr Sect E Struct Rep Online ; 64(Pt 8): o1438, 2008 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-21203153

RESUMO

In the title compound, C(24)H(21)NO(2)·C(2)H(6)O, the dihedral angle between the two aromatic ring systems is 87.00 (6)°. There is an intra-molecular O-H⋯N hydrogen bond, which forms a six-membered ring. Inter-molecular O-H⋯O hydrogen bonds stabilize the crystal structure.

12.
Huan Jing Ke Xue ; 28(2): 304-8, 2007 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-17489188

RESUMO

With batch culture experiments in field and laboratory, the ecological effect of No. 0 diesel water accommodated fraction on marine algae was studied. A growth model of marine algae under grazing pressure and a model of growth effect on marine algae with different doses No.0 diesel water accommodated fraction were proposed. Based on the model and experiments, the growth effect of No.0 diesel water accommodated fraction on marine algae was studied. The results show that, the growth model of marine algae under grazing pressure is more suited for the marine ecological system than Logistic model. And the final biomass (B(f)) of marine algae with different doses No.0 diesel water accommodated fraction was calculated by the model with none-linear fitting software. The results also show that, under the field and laboratory conditions, lower doses No.0 diesel water accommodated fraction promotes the growth of marine algae, and the most promoting ratio are 180% and 120% respectively, however, higher doses hardly promotes but bates the growth of marine algae.


Assuntos
Eucariotos/crescimento & desenvolvimento , Gasolina , Fitoplâncton/crescimento & desenvolvimento , Poluentes Químicos da Água/análise , Ecossistema , Modelos Teóricos , Oceanos e Mares
13.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 35(1): 47-9, 2004 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-14981813

RESUMO

OBJECTIVE: To study the expression of vascular endothelial growth factor C (VEGF-C) in laryngeal squamous carcinoma (LSC) and its relationship to lymph node metastasis. METHODS: Paraffin-embedded specimens of primary laryngeal carcinomas from 60 patients subjected to operation were studied. VEGF-C expression was investigated using immunohistochemical staining. RESULTS: Positive immunohistochemical staining for VEGF-C protein was observed in some laryngeal squamous carcinoma cells (45/60), the VEGF-C antigen was identified in the cytoplasm of cancer cells. Furthermore, the expression of VEGF-C in laryngeal squamous carcinoma cells was significantly higher in lymph-node-positive groups than in node-negative groups, and the expression was significantly higher in poorly differentiated LSC tissues than in moderately and well differentiated LSC tissues. CONCLUSION: The above findings indicate a close correlation between VEGF-C expression and lymph node metastasis in laryngeal squamous carcinoma.


Assuntos
Carcinoma de Células Escamosas/metabolismo , Neoplasias Laríngeas/metabolismo , Fator C de Crescimento do Endotélio Vascular/biossíntese , Adulto , Idoso , Biomarcadores Tumorais , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Laríngeas/patologia , Metástase Linfática , Masculino , Fator C de Crescimento do Endotélio Vascular/genética
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