Synthesis of Se polysaccharide catalyzed by sulfonic acid functionalized ionic liquids: Synergism effect of anion/cation.

The rational design and construction of controllable selenylation strategy are important for the study on the structure-activity relationship of Se polysaccharides. Herein, selenized Artemisia sphaerocephala polysaccharides (SePASs) were synthesized by using sulfonic acid functionalized ionic liquids (SFILs) as catalysts in order to study the regulation of the cation/anion constitute on the selenylation efficiency and Se polysaccharide structure. Impressively, SFILs could promote the efficient substitution of seleno-group on the polysaccharide backbone through the synergistic catalysis by cation/anions (Se content up to 5582.7 µg/g). Further, reaction mechanism and potential dissolution effect was supported by DFT calculation and polarized light microscopy. 13C NMR and FT-IR spectra analysis of SePASs exhibited that selenite existed in polysaccharides and the substitution position occured at C-6. SEC-MALLS, monosaccharide composition results revealed that strong acidity of SFILs lead to the driving forces toward low molecular mass polysaccharide fragments and synergistic effect of anion/cations in SFILs (-SO3H group of cations as proton donor, anions as nucleophile) showed regulation on average molecular mass. In addition, the strong attractions between the seleno-groups generated agglomeration of polysaccharide chain, which was proved by applying AFM analysis. Therefore, this work provided a new insight for manipulate Se content and MW of Se polysaccharides.

SIAH2 regulates colorectal cancer tumorigenesis via PI3K/ATK signaling pathway.

Colorectal cancer (CRC) is the third most common cancer and the 4th leading cause of cancer-related deaths, although with a dismal prognosis. The SIAH E3 Ubiquitin Protein Ligase 2 (SIAH2) regulates the expression of multiple proteins via ubiquitination and proteasome. However, the biological role of SIAH2 in colorectal cancer tumorigenesis remains controversial. In this work, we found that SIAH2 is an oncogene in colorectal cancer. Moreover, SIAH2 promoted colorectal cancer cell proliferation, migration, invasion, and colony formation. Mechanistically, SIAH2 promoted the PI3K/AKT signaling pathway both in vivo and in vitro. Besides, we discovered that PTEN loss regulates SIAH2-mediated PI3K/AKT signaling pathway activation. In summary, these findings highlight the role of SIAH2 in colorectal cancer progression and provide novel insights for treatment.

Efficient synthesis of polysaccharide with high selenium content mediated by imidazole-based acidic ionic liquids.

Exploring new solvents or catalysts has great prospect for the derivatization of poorly soluble natural polysaccharides as bio-resources which were extracted from food or industrial waste residue, as compared to traditional reaction system. In this work, selenized Artemisia sphaerocephala polysaccharide (SePAS) was synthesized by using imidazolium-based acidic ionic liquids (AILs) as catalyst. The results showed the highest Se content increased to 20438 µg/g compared to conventional method (1703 µg/g), indicating AILs could enhance selenylation reactivity and Se content was controlled by the acidity due to the protonation effect of H2SeO3 by AILs. FT-IR, X-ray photo-electron spectroscopy (XPS) and 13C NMR results exhibited that seleno-group exists in SePAS and the substitution position was at C-6. The hydrogen bonding effect and acidity of AILs showed regulation on weight average molecular mass of SePAS. Therefore, AILs with excellent catalytic efficiency could be as potential catalyst for full use of polysaccharide-rich resources.

2'-Fluoro-3',5'-dimethoxy-acetanilide.

Mol-ecules of the title compound, C(10)H(12)FNO(3), are nearly planar considering all non-H atoms with a mean deviation of 0.0288 Å. Mol-ecules are linked through inter-molecular N-H⋯O and N-H⋯F hydrogen bonds.

Phosphine-catalyzed [3+2] annulations of γ-functionalized butynoates and 1C,3O-bisnucleophiles: highly selective reagent-controlled pathways to polysubstituted furans.

In this paper, a reagent-controlled [3+2] annulation of γ-functionalized butynoates 1 and 1C,3O-bisnucleophiles 2 is reported, which leads to three distinct furan skeletons 3-5. A PPh(3) catalyst preferentially attached the ß-position of 1a, facilitating α-addition to furnish Type I annulations. With the assistance of Ag(2)O, Type II annulations were achieved via selective γ-substitution. In the absence of the PPh(3) catalyst, the reagent Cs(2)CO(3) promoted ß-addition to realize Type III annulations.