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1.
Angew Chem Int Ed Engl ; 61(51): e202215020, 2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36283979

RESUMO

A novel and expedient cascade strategy has been demonstrated for the synthesis of fused benzo-aza-oxa-[5-6-5] tetracycles in high yields and diastereoselectivities (up to 20 : 1 dr). The strategy was fulfilled through palladium-catalyzed oxidative convergent assembly of functionally divergent anilines and 3-butenoic acid with five chemical bonds constructed. Coupled with control experiments and deuterium labelled studies, DFT calculations were performed for the proposed mechanism. The utility of the illustrated strategy is emphasized by gram-scale syntheses, late-stage functionalization, and the transformation to a key core of natural products such as martinellic acid and seneciobipyrrolidine.


Assuntos
Paládio , Paládio/química , Catálise , Ciclização
2.
Can J Microbiol ; 65(12): 913-921, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491332

RESUMO

This study reports the use of reverse transcription - loop-mediated isothermal amplification (RT-LAMP) to detect Listeria monocytogenes in meat. The assay was designed to target the iap gene of L. monocytogenes, to which four primers, recognizing six distinct iap sites, were designed. We optimized the RT-LAMP conditions and established the following optimal systems: 60 min, 63 °C, 2.0 mmol/L MgSO4, 1.0 mol/L betaine, 2.0 mmol/L dNTPs, 320 U/mL Bst DNA polymerase, 0.4 µmol/L outer primers, and 0.8 µmol/L inner primers. The RT-LAMP amplification products were identified by a visible white Mg2P2O7 precipitate or electrophoresis on a 2% agarose gel. RT-LAMP has a sensitivity of 7.3 × 101 CFU/mL, which is 2-fold higher than that of LAMP. When commercially available raw meat samples (including beef, pork, mutton, and rabbit) were analyzed simultaneously with RT-LAMP and the Chinese National Standard GB 4789.30-2016, their abilities to detect L. monocytogenes were the same. Samples containing L. monocytogenes killed by 15 psi at 121 °C for 15 min were used to confirm the specificity of RT-LAMP for live microorganisms. Thus, we used RT-LAMP to efficiently detect L. monocytogenes in meat products.


Assuntos
Microbiologia de Alimentos/métodos , Listeria monocytogenes/isolamento & purificação , Produtos da Carne/microbiologia , Técnicas de Amplificação de Ácido Nucleico , Animais , Proteínas de Bactérias/genética , Lipoproteínas/genética , Listeria monocytogenes/genética , Carne/microbiologia , Sensibilidade e Especificidade
3.
Org Lett ; 20(3): 550-553, 2018 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-29368932

RESUMO

A novel palladium-catalyzed amination and nitration of ethyl vinyl ether for the construction of ß-nitroamine derivatives under mild conditions has been developed. This transformation provides a new strategy for the installation of amino and nitro from aromatic amines and nitro-paraffin into alkenes. Morpholine resulted in the aza-Henry reaction, while DABCO led to the unexpected rearrangement.

4.
Artigo em Inglês | MEDLINE | ID: mdl-26160605

RESUMO

Two new organic-inorganic molecular solids of tetra(isothiocyanate)cobalt(II) dianion and disubstituted benzyl triphenylphosphinium, [2Cl4FBzTPP]2[Co(NCS)4] (1) and [2Cl4ClBzTPP]2[Co(NCS)4] (2) ([2Cl4FBzTPP](+)=1-(2'-chloro-4'-fluorobenzyltriphenylphosphonium) and [2Cl4ClBzTPP](+)=1-(2',4'-dichlorobenzyltriphenylphosphonium), were synthesized and characterized by elemental analysis, FT-IR, UV-Vis spectra, ESI-MS and single crystal X-ray diffraction method. Compounds 1 and 2 crystallize in the monoclinic Pc and triclinic P-1, respectively. The Co(II) ion of the [Co(NCS)4](2-) anion shows a distorted tetrahedral coordination geometry. The [2Cl4FBzTPP](+) cations containing P(2) atoms in 1 form a column by the Cl⋯π interactions, while the [2Cl4ClBzTPP](+) cations in 2 form two columns by the C-H⋯π and π⋯π interactions. The anion and the cation are linked by C-H⋯S hydrogen bonds and Cl⋯S interactions. Magnetic susceptibility measurement in the temperature range 2-300K shows that both 1 and 2 exhibit a weak antiferromagnetic exchange interaction as the temperature falls, and ultraviolet fluorescence emission in the solid state at room temperature.

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