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1.
J Org Chem ; 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31859499

RESUMO

A series of novel bis-BN-naphthalene-fused oxepin derivatives were synthesized via a Pd-catalyzed tandem reaction from brominated 2,1-borazaronaphthalenes and cis-bis(boryl)alkenes. X-ray crystallographic analysis revealed that bis-BN-naphthalene-fused oxepins feature a planar framework. The electronic and photophysical properties of the novel BN-naphthalene-fused oxepins were investigated by UV-vis and fluorescence spectroscopies and density functional theory (DFT) calculations, which disclosed the distinct electronic and photophysical properties of the analogous hydrocarbon system. Interestingly, dual-fluorescent emissions were observed upon dissolving N-substituted derivatives 10-14 in dimethyl sulfoxide. Tunable emission colors especially for white-light emissions can be achieved by controlling the ratio of solvents, concentration, or temperature using only a single-molecule compound.

2.
Chem Commun (Camb) ; 55(97): 14697-14700, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31750472

RESUMO

A cascade radical cyclization was realized for the first silver-promoted imino-phosphorylation of γ,δ-unsaturated oxime esters, which provided a step-economical and redox-neutral route to access a variety of phosphorylated pyrrolines in good to excellent yields. Moreover, a new bulky trivalent phosphine ligand with a pyrroline motif was obtained through a deoxidation process.

3.
Chem Commun (Camb) ; 55(81): 12235-12238, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31552940

RESUMO

A new calixpyridinium-based light-responsive host-guest recognition motif was found in this work. This host-guest recognition motif was further discovered to be applied as a selective turn-on fluorescent sensor for lysine over other natural amino acids.

4.
Org Biomol Chem ; 17(33): 7679-7683, 2019 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-31386754

RESUMO

The first example of pyrazole-directed rhodium(iii)-catalyzed unreactive C(sp3)-H alkenylation with alkynes has been described, which showed a relatively broad substrate scope with good functional group compatibility. Moreover, we demonstrated that the transitive coordinating center pyrazole could be easily removed under mild conditions.

5.
Org Biomol Chem ; 17(36): 8358-8363, 2019 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-31465083

RESUMO

A palladium-catalyzed cascade reaction of alkene-tethered carbamoyl chlorides with N-tosyl hydrazones is described. It provided a new way to synthesize various alkene-functionalized oxindoles bearing an all-carbon quaternary center. The olefin moieties could serve as versatile handles for further elaboration. This transformation was highly efficient and showed good functional group tolerance.

6.
J Pharm Biomed Anal ; 176: 112803, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31442761

RESUMO

In the present paper, a sensitive and selective chiral LC method has been developed for enantiomeric separation and determination of eight antihistamines in pharmaceutical formulations. Enantiomeric separation was achieved on the α1-acid glycoprotein-based chiral stationary phase known as Chiralpak AGP. The effects of the mobile phase composition, type and proportion of organic modifier and the concentration and pH of the buffer on retention and resolution were fully investigated. All enantiomers of target analytes were successfully separated with the mobile phase consisting of methanol and 10 mM ammonium acetate buffer, at a flow rate of 0.9 mL min-1. Calibration curve of each enantiomer was linear over the concentration range of 5.0-100 µg mL-1, with the correlation coefficient above 0.9990. The limits of detection and quantification were below 0.80 and 3.18 µg mL-1, respectively. The recoveries were in the range of 98.0-102.4% with the relative standard deviation lower than 2.88% for all enantiomers. The validated method was demonstrated to be suitable for the quality control of the enantiomeric composition of antihistamines present in pharmaceuticals. Finally, the proposed chiral LC method was applied to the determination of antihistamines enantiomers in commercially available tablets containing racemic mixtures of compounds. Quantitative results of the commercial tablets demonstrated that the difference between the declared and determined values did not exceed 1.45%, and chiral antihistamines drugs were present in the form of racemates.

7.
Langmuir ; 35(32): 10505-10511, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31310550

RESUMO

In this work, cationic macrocyclic calixpyridinium was employed as a new strategy to condense DNA. Moreover, the degradation of DNA by DNase I could lead to the calixpyridinium-DNA supramolecular aggregates being dissipated. Therefore, the present system is potentially applicable as the targeted drug delivery model at DNase I-overexpressed sites.

8.
Food Chem ; 300: 125241, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31352289

RESUMO

In stock farming, illegal use of antipsychotics has caused the food safety problem. This paper presents for the first time, a multi-residues method for the simultaneous enantioselective determination of seven antipsychotics in pork, beef and lamb muscles. The behaviors of Chiralpak AGP toward changes in pH and organic modifier in mobile phase were studied, and all analytes were rapidly separated within 30 min. The calibration curves of all enantiomers were linear in the range of 1-250 ng g-1, with correlation coefficient above 0.9931. The recoveries of the targeted compounds were higher than 82.1%, with repeatability and intermediate precision lower than 18.2% and 17.4%, respectively. In three matrices, the limit of detection and limit of quantification ranged from 0.20 to 0.65 ng g-1 and from 0.40 to 1.00 ng g-1, respectively. The proposed method can be used to provide additional information for the reliable risk assessment of chiral antipsychotics.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Produtos da Carne/análise , Psicotrópicos/análise , Espectrometria de Massas em Tandem/métodos , Animais , Calibragem , Bovinos , Cromatografia de Fase Reversa/métodos , Análise de Alimentos/métodos , Limite de Detecção , Psicotrópicos/química , Reprodutibilidade dos Testes , Ovinos , Estereoisomerismo , Suínos
9.
J Org Chem ; 84(14): 8984-8997, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31250644

RESUMO

An In(OTf)3-catalyzed domino reaction involving sequential oxidative ring opening of aziridines by using the solvent dimethyl sulfoxide and intramolecular Michael addition has been developed for the modular synthesis of 2-aminoindanone compounds by the formation of one new C═O bond and one new C-C bond. The notable feature of this strategy includes broad substrate scope, excellent trans-diastereoselectivities, highly functionalized products, and mild conditions. The catalyst In(OTf)3 plays an important role in the formation of the indanone ring.

10.
Langmuir ; 35(27): 9020-9028, 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31203624

RESUMO

In this work, the host-guest interaction between calixpyridinium and anionic anticancer drug Alimta was studied in aqueous media. Spherical supramolecular amphiphilic assembly rather than simple complex was accidentally fabricated by the complexation of calixpyridinium with Alimta. It is the third kind of anionic guest to be discovered to form the higher-order assembly by the complexation of calixpyridinium besides polyanionic guest and anionic gemini surfactant guest. The finding of this assembly approach supplies a new idea to construct various self-assembly architectures in water via the complexation of calixpyridinium with anionic drugs. The resulting calixpyridinium-drug assemblies may also have the potential to adjust the effects of drugs.

11.
Anal Bioanal Chem ; 411(14): 3021-3028, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30888466

RESUMO

A novel fluoro-chromogenic rhodamine spirolactam probe (RP) has been prepared through the condensation of rhodamine hydrazine and 2-acetylpyridine, which displayed the detection of Cu2+ with high selectivity over a large number of other common metal ions. It shows a "turn-on" response to paramagnetic Cu2+ with an about 12-fold enhancement, and a color change from colorless to red that is observable by the naked eye. These changes are ascribed to the ring-opening of the spirolactam in RP, and subsequent host-guest coordination. The 2:1 binding stoichiometry of RP to Cu2+ was confirmed by Job's and B-H plots. The resulting fluorescence enhancement can be used to detect Cu2+ at concentrations from 2.0 to 20.0 µM with a limit of detection of 0.21 µM, which was lower than the maximum allowable Cu2+ level set by the WHO. Finally, RP has been utilized to monitor Cu2+ in living cells and natural water. Graphical abstract.


Assuntos
Cobre/análise , Corantes Fluorescentes/química , Macrófagos/citologia , Piridinas/química , Rodaminas/química , Animais , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Cristalografia por Raios X , Limite de Detecção , Camundongos , Estrutura Molecular , Espectroscopia de Prótons por Ressonância Magnética , Células RAW 264.7 , Espectrometria de Fluorescência , Água/química
12.
Org Lett ; 20(21): 6640-6645, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30350669

RESUMO

A novel palladium-catalyzed, norbornene-mediated intermolecular dehydrogenative annulation approach for the synthesis of 6-fluoroalkyl-phenanthridines from aryl iodides and fluorinated imidoyl chlorides, which are important structural motifs for bioactive molecules, is reported. Fluorinated imidoyl chlorides served as a new type of electrophilic reagent in the Catellani-type reaction, which, in turn, could be readily prepared from various anilines and fluorinated carboxylic acids. Control experiments were carried out to study the mechanism of the reaction. This transformation is scalable and tolerates a broad range of functional groups.

13.
Org Lett ; 20(18): 5680-5683, 2018 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-30188133

RESUMO

A dramatic N-substituent controlled tandem annulation of 2-(2-(2-bromoethyl)phenyl)-1-sulfonylaziridines with 1,3-dicarbonyl compounds has been developed. When the N-substituent was a 4-methylbenzenesulfonyl group (Ts), sequential ring opening of aziridines, nucleophilic substitution, and lactamization took place to provide a series of hexahydrobenz[ e]isoindole compounds in good yields with good diastereoselectivities. By contrast, 3-benzazepine compounds were afforded in good yields via ring opening of aziridines and nucleophilic substitution when the N-substituent was the 4-nitrobenzenesulfonyl group (Ns).

14.
Org Biomol Chem ; 16(27): 5021-5026, 2018 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-29946617

RESUMO

A facile and practical [Cp*RhCl2]2-catalyzed three-component reaction between indolyl aldehydes, amines and alkynes involving C-H activation and cyclization has been developed. A series of ß-carbolinium salts and γ-carbolinium salts are successfully afforded in good to quantitative yields under mild conditions. This efficient and convergent strategy provides a good choice for constructing the libraries of ß-carbolinium salts and γ-carbolinium salts.

15.
Electrophoresis ; 39(19): 2398-2405, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29947082

RESUMO

The enantioseparation of twelve pairs of structurally related 1-aryl-1-indanone derivatives was studied in the normal-phase mode using three different polysaccharide-type chiral stationary phases, namely Chiralpak IB, Chiralpak IC, and Chiralpak ID. n-Hexane/2-propanol and n-hexane/ethanol were employed as mobile phases. Among all the investigated chiral columns, Chiralpak IC exhibited the most universal and the best enantioseparation ability toward all the racemates, particularly with the mobile phase composed of n-hexane/2-propanol (90/10, v/v). Then the effects of column temperature on retention and enantioselectivity were examined in the range of 25-40°C. Satisfactory enantioseparation was obtained at ambient temperature. The natural logarithm of retention and separation factors (ln k and ln α) versus the reciprocal of absolute temperature (1/T) (Van't Hoff plots) were found to be linear for all racemates, indicating that the retention and separation mechanisms were independent of temperature in the range investigated. Then, the thermodynamic parameters (ΔΔH°, ΔΔS°, and ΔΔG°) were calculated from Van't Hoff plots. These values indicated that the solute transfer from the mobile to stationary phase was enthalpically favorable, and the process of enantioseparation was mainly enthalpy controlled. At last, the impact of small changes in molecular structures of the tested 1-indanone derivatives on enantioseparation was also discussed.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Modelos Químicos , Polissacarídeos/química , Cromatografia Líquida de Alta Pressão/instrumentação , Indanos/análise , Indanos/química , Indanos/isolamento & purificação , Estereoisomerismo , Termodinâmica
16.
Electrophoresis ; 39(16): 2107-2116, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29775209

RESUMO

Immobilized polysaccharide-based columns showed excellent enantioselectivity in normal phase separation mode. In this work, enantioseparation abilities of four immobilized polysaccharide-derived chiral stationary phases (Chiralpak IA, Chiralpak IB, Chiralpak IC, and Chiralpak ID) toward 15 azole compounds were evaluated. Separation was carried out using n-hexane as mobile phase with ethanol, 1-propanol, 1-butanol, and 2-propanol as modifiers. And twelve compounds have achieved baseline separation with the resolutions ranging between 2.05 and 21.73. The enantioseparation on the four polysaccharide-based chiral columns using different alcohol modifiers was compared. In general, the best separation performance was identified as Chiralpak IC, which was able to resolve 11 compounds to baseline and two partially under the screening conditions. Separation on Chiralpak IB was not satisfactory, because only four compounds were baseline separated.


Assuntos
Azóis/isolamento & purificação , Estereoisomerismo , Álcoois , Azóis/química , Cromatografia Líquida de Alta Pressão/métodos , Hexanos , Métodos , Polissacarídeos
17.
J Pharm Biomed Anal ; 156: 88-96, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29698862

RESUMO

In this work, a nanocomposite, Fe3O4/graphene was prepared and characterized. Five profens (including ibuprofen, flurbiprofen, pranoprofen, indoprofen and loxoprofen sodium) were extracted from three environmental water samples by using the synthetic Fe3O4/graphene, followed by simultaneous determination of the enantiomers on a Chiralcel OJ-RH column coupled with a triple quadrupole mass spectrometry. Factors affecting the extraction efficiency, such as amount of adsorbents, solution pH, ionic strength, type and volume of desorption solvent, as well as elution time were thoroughly investigated. Method validation showed high sensitivity with method quantification limits in the range of 8.49-26.3 ng/L. Satisfactory recovery (73.6-90.2%), good intra-day precision (RSD 3.2-9.7%) and inter-day precision (RSD 5.2-10%) were also obtained. Furthermore, possible interactions between analyte and graphene, such as electrostatic attraction, charge-π interaction, hydrophobic interaction and π-π stacking were discussed by combining the experiment results and molecular docking study, which provided a new insight into the adsorption mechanism of graphene.


Assuntos
Grafite/química , Nanocompostos/química , Fenilpropionatos/análise , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Adsorção , Limite de Detecção , Nanopartículas de Magnetita/química , Espectrometria de Massas , Microscopia Eletrônica de Transmissão , Simulação de Acoplamento Molecular , Concentração Osmolar , Estereoisomerismo
18.
Chirality ; 30(5): 642-651, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29406589

RESUMO

The enantioseparation of ezetimibe stereoisomers by high-performance liquid chromatography on different chiral stationary phases, ie, 3 polysaccharide-based chiral columns, was studied. It was observed that cellulose-based Chiralpak IC column exhibited the best resolving ability. After the optimization of mobile phase compositions in both normal and reversed phase modes, satisfactory separation could be obtained on Chiralpak IC column, especially in normal phase mode. The use of prohibited solvents as nonstandard mobile phase gave rise to better resolution than that of standard mobile phases (n-hexane/alcohol system). In addition, the presence of ethanol in nonstandard mobile phase has played an important role in enhancing chromatographic efficiency and resolution between ezetimibe stereoisomers. Various attempts were made to comprehensively compare the chiral recognition capabilities of immobilized versus coated polysaccharide-based chiral columns, amylose-based versus cellulose-based chiral stationary phases, reversed versus normal phase modes, and standard versus nonstandard mobile phases. Moreover, possible solute-mobile phase-stationary phase interactions were derived to explain how stationary and mobile phases affected the separation. Then the method validation with respect to selectivity, linearity, precision, accuracy, and robustness was carried out, which was demonstrated to be suitable and accurate for the quantitative determination of (RRS)-ezetimibe impurity in ezetimibe bulk drug.

19.
ACS Omega ; 3(4): 4522-4533, 2018 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31458676

RESUMO

Reactions of two dinaphthyl phosphines with [Cp*IrCl2]2 have been carried out. In the case of di(α-naphthyl)phenylphosphine (1a), a simple P-coordinated neutral adduct 2a is obtained. However, tert-butyldi(α-naphthyl)phenylphosphine (1b) is cyclometalated to form [Cp*IrCl(P^C)] (3b). Complexes 2a and 3a undergo further cyclometalation to give the corresponding double cyclometalated complexes [Cp*Ir(C^P^C)] (4a,b) upon heating. In the presence of sodium acetate, reactions of 1a,b with [Cp*IrCl2]2 directly afford the final double cyclometalated complexes (4a,b). In the absence of acetate, [Cp*RhCl2]2 shows no reaction with 1a,b, whereas with acetate the reactions form the corresponding single cyclometalated complexes [Cp*RhCl(P^C)] (5a,b), which react with t BuOK to form the corresponding rhodium hydride complexes (6a,b). Treatment of 4a with CuCl2 or I2 leads to opening of two Ir-C σ bonds to yield the corresponding P-coordinated iridium dihalide (7 or 8) by means of an intramolecular C-C coupling reaction. A new chiral phosphine (11) is formed by the ligand-exchange reaction of 8 with PMe3. Reactions of the single cycloiridated complex 3b with terminal aromatic alkynes result in the corresponding five- and six-membered doubly cycloiridated complex 12 and/or η2-alkene coordinated complexes 13-15; the latter discloses that the electronic effect of terminal alkynes affects the regioselectivity. While the single cyclorhodated complex 5b reacts with terminal aromatic alkynes to form the corresponding six-membered cyclometalated complexes 16a-c by vinylidene rearrangement/1,1-insertion. Plausible pathways for formation of insertion products 13-16 were proposed. Molecular structures of twelve new complexes were determined by X-ray diffraction.

20.
ACS Omega ; 3(8): 10033-10041, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31459131

RESUMO

In this work, a comparative study on the supramolecular assemblies formed by calixpyridinium and two alginates with different viscosities was performed. We found that sodium alginate (SA) with medium viscosity (SA-M) had a better capability to induce aggregation of calixpyridinium in comparison with SA with low viscosity (SA-L) because of the stronger electrostatic interactions between calixpyridinium and SA-M. Therefore, the morphology of calixpyridinium-SA-M supramolecular aggregates was a compact spherical structure, while that of calixpyridinium-SA-L supramolecular aggregates was an incompact lamellar structure. As a result, adding much more amount of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt to calixpyridinium-SA-M solution was required to achieve the balance of the competitive binding, and in comparison with calixpyridinium-SA-L supramolecular aggregates, calixpyridinium-SA-M supramolecular aggregates were more sensitive to alkali. However, for the same reason, in comparison with calixpyridinium-SA-M supramolecular aggregates, calixpyridinium-SA-L supramolecular aggregates were much more stable in water not only at room temperature but also at a higher temperature, and even in salt solution. Therefore, in comparison with calixpyridinium-SA-L supramolecular aggregates, calixpyridinium-SA-M supramolecular aggregates exhibited a completely opposite response to acid because of the generation of salt. Because SA is an important biomaterial with excellent biocompatibility, it is anticipated that this comparative study is extremely important in constructing functional supramolecular biomaterials.

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