ABSTRACT
Transition-metal-catalyzed aromatic olefination through direct C-H activation represents an atom and step-economic route for versatile pharmaceutical syntheses, and in many cases, different stoichiometric oxidants are frequently employed for achieving a reasonable catalytic efficiency of the transition metal ions. Herein, we report a Lewis acid promoted Pd(II)-catalyzed acetanilide olefination reaction with atmospheric dioxygen as the oxidant source. The linkage of the Lewis acid to the Pd(II) species through a diacetate bridge significantly improved its catalytic efficiency, and independent kinetic studies on the olefination step revealed that adding the Lewis acid significantly accelerated the olefination rate as well as the C-H activation step. A strong basicity of the internal base in the Pd(II) salt also benefited the olefination reaction plausibly through base-assisted ß-hydride elimination.
ABSTRACT
Aniline derivatives are important nitrogen-containing compounds with wide applications in chemicals, pharmaceuticals and agrochemicals. In the work described herein, nickel(II)/Lewis acid (LA) catalysed olefin hydroamination with anilines was explored for use in aniline derivative syntheses. The Ni(II)/LA catalysis proceeded smoothly under mild conditions, whereas using Ni(OAc)2 alone, the catalyst was inactive. Remarkably, the Markovnikov addition type products were obtained when substituted styrenes were used as the olefin source, while the anti-Markovnikov addition type products were obtained when the electron-deficient olefins such as acrylonitrile and acrylates were used. The mechanistic studies revealed that hydroamination of the styrene derivates proceeded via the amino-Ni(II)/LA attacking the carbocation intermediate which was generated by the protonation of the olefin, whereas for acrylonitrile and acrylates, it proceeded by a direct amino-Ni(II)/LA attack on the olefin by nucleophilic addition. In addition, the hydroarylation product was generated by the Hofmann-Martius rearrangement of the hydroamination product.
ABSTRACT
A metal-free, water-tolerant, and one-pot process for ortho-acylation of phenols promoted by the iodine source/hydrogen peroxide system has been developed. This transformation undergoes ether formation, iodocyclization, C-C bond cleavage, and oxidative hydrolysis in a one-step manner, which is supported by control experiments.
ABSTRACT
BACKGROUND Metastasis contributes to the high mortality rate of non-small cell lung cancer (NSCLC), and gaining a better understanding of its metastatic mechanisms would aid in initiating effective clinical treatment. MATERIAL AND METHODS In this study, bioinformatics analyses of the GEO database and TCGA-LUAD were first used to identify the key node gene regulating NSCLC malignant progression. Further in vitro experiments, including wound healing assay, invasion assay, Western blot assay, and luciferase report assay, were used to clarify the functions and mechanism of TPX2 in NSCLC. RESULTS Results of the TCGA analysis showed that TPX2 was significantly positively correlated with tumor metastasis and growth and the clinical stage of NSCLC. In addition, high levels of TPX2 significantly indicated a poor survival rate. In vitro experimental results also revealed that the upregulation of TPX2 significantly promoted NSCLC cell migration and invasion and could affect cell replasticity. Further results indicated that TPX2 significantly activated the epithelial-mesenchymal transition process and promoted the expression and activities of matrix metalloproteinase (MMP)2 and MMP9. CONCLUSIONS This study demonstrated that TPX2 promotes the metastasis and malignant progression of NSCLC and could thus serve as a marker of poor prognosis in NSCLC.
