ABSTRACT
Copper-catalyzed dearomatization and difunctionalization of pyridines have been disclosed, in which bromodifluoro-N-arylacetamide was sliced into five fragments and three or four of them were transferred to pyridine partners. Through this reaction, novel N-difluoromethyl-2-imine dihydropyridine derivatives can be conveniently accessed from commercially available 4-amino substituted pyridines. This strategy demonstrates a novel fluorination method featuring high atom economy, environmental friendliness, an easily available catalyst, and simple operation.
ABSTRACT
Ambipolar organic field-effect transistors (OFETs) are vital for the construction of high-performance all-organic digital circuits. The bilayer p-n junction structure, which is composed of separate layers of p- and n-type organic semiconductors, is considered a promising way to realize well-balanced ambipolar charge transport. However, this approach suffers from severely reduced mobility due to the rough interface between the polycrystalline thin films of p- and n-type organic semiconductors. Herein, 2D molecular crystal (2DMC) bilayer p-n junctions are proposed to construct high-performance and well-balanced ambipolar OFETs. The molecular-scale thickness of the 2DMC ensures high injection efficiency and the atomically flat surface of the 2DMC leads to high-quality p- and n-layer interfaces. Moreover, by controlling the layer numbers of the p- and n-type 2DMCs, the electron and hole mobilities are tuned and well-balanced ambipolar transport is accomplished. The hole and electron mobilities reach up to 0.87 and 0.82 cm2 V-1 s-1 , respectively, which are the highest values among organic single-crystalline double-channel OFETs measured in ambient air. This work provides a general route to construct high-performance and well-balanced ambipolar OFETs based on available unipolar materials.
ABSTRACT
An efficient oxydifluoroalkylation of hydroxyl-containing alkenes using a copper catalytic system has been developed. This reaction proceeded through a one-pot process of difluoroalkylation followed by nucleophilic attack of the appended hydroxyl group. This strategy has the advantages of a low-cost catalyst and broad substrate scope, which provides a facile access to various fluoroalkylated tetrahydrofurans and tetrahydropyrans.
ABSTRACT
BACKGROUND: Oral lichen planus (OLP) is a chronic and T cell-mediated autoimmune disease whose immunopathogenesis may involve antigen-presentation, T cells activation and migration as well as keratinocytes apoptosis. PD-1/B7-H1 pathway may have a unique function in regulating self-reactive T cells associated with inflammatory response and maintaining tolerance in peripheral tissues. In this study, we aimed to explore the contribution of PD-1/B7-H1 pathway to OLP. METHODS: We determined the expression of PD-1 and B7-H1 on peripheral blood T cells from OLP cases and analyzed their association with disease severity assessed by RAE (reticular, atrophic and erosive lesion) scoring system. In addition, interferon-γ, interleukin (IL)-2, IL-4, IL-10 and soluble PD-1 concentrations in serum were measured using ELISA. Then, we explored the regulation of PD-1/B7-H1 pathway on T cells immune response in OLP by blockade of PD-1 or B7-H1. RESULTS: We found that PD-1 and B7-H1 were up-regulated on peripheral blood T cells from OLP patients and B7-H1 expression positively correlated with disease severity of OLP. It is suggested that Th1 dominant inflammatory situation might contribute to the high expression of PD-1 and B7-H1 in OLP. Blockade of PD-1/B7-H1 pathway significantly increased the proliferation, and IFN-γ and IL-2 production of T cells. CONCLUSIONS: PD-1/B7-H1 pathway may play an important role in negatively modulating T cell-mediated immune response in OLP, and provide the rationale to employ B7-H1 expression on peripheral blood T cells as a marker of severity of OLP and to develop agonists targeting PD-1/B7-H1 pathway as a promising immunotherapeutic strategy for OLP.