RESUMO
We developed an asymmetric decarboxylative allylic alkylation of vinylethylene carbonates with α-fluoro pyridinyl acetates through a synergistic palladium/copper catalysis. This protocol provides chiral allylic alcohol with carbon-fluorine quaternary stereogenic centers in good yield with good enantioselectivities and excellent regioselectivities. The utility of this approach was further demonstrated via a gram-scale experiment and derivatizations of the product.
RESUMO
In this paper, a certain amount of rare earth (europium) was doped into magnesium aluminum salt solution and assembled with graphene oxide (GO) by electrostatic interaction under alkaline conditions. Then, the EuMgAl-LDH/GO hybrid material was synthesized by a hydrothermal method. Its microstructure was analyzed and tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR), the results indicated that the EuMgAl-LDH/GO hybrid material had been successfully prepared. Next, it was mixed with zinc borate and added to a thermoplastic polyurethane (TPU) (thermoplastic polyurethane) matrix by melting blending. The flame retardant and smoke suppression effect of the composite was tested by conical calorimetry. The results showed that, compared with simple TPU, the PHRR (peak heat release rate), THR (total heat release), PSPR (peak smoke production rate) and TSP (total smoke production) value of the composite material decreased by 65.6%, 16.2%, 61% and 37.1%, respectively. Finally, through analysis of the carbon residue after combustion of the TPU composite material, we found that the formed carbon layer is denser and the char yield is greatly improved.
RESUMO
The increase in fructose consumption is considered to be a risk factor for developing nonalcoholic fatty liver disease (NAFLD). We investigated the effects of docosahexaenoic acid (DHA) on hepatic lipid metabolism in fructose-treated primary mouse hepatocytes, and the changes of Endoplasmic reticulum (ER) stress pathways in response to DHA treatment. The hepatocytes were treated with fructose, DHA, fructose plus DHA, tunicamycin (TM) or fructose plus 4-phenylbutyric acid (PBA) for 24 h. Intracellular triglyceride (TG) accumulation was assessed by Oil Red O staining. The mRNA expression levels and protein levels related to lipid metabolism and ER stress response were determined by real-time PCR and Western blot. Fructose treatment led to obvious TG accumulation in primary hepatocytes through increasing expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), two key enzymes in hepatic de novo lipogenesis. DHA ameliorates fructose-induced TG accumulation by upregulating the expression of carnitine palmitoyltransferase 1A (CPT-1α) and acyl-CoA oxidase 1 (ACOX1). DHA treatment or pretreatment with the ER stress inhibitor PBA significantly decreased TG accumulation and reduced the expression of glucose-regulated protein 78 (GRP78), total inositol-requiring kinase 1 (IRE1α) and p-IRE1α. The present results suggest that DHA protects against high fructose-induced hepatocellular lipid accumulation. The current findings also suggest that alleviating the ER stress response seems to play a role in the prevention of fructose-induced hepatic steatosis by DHA.