Brønsted acid-mediated tandem cyclization of triarylphosphines and generated -alkynyl quinone methides: access to heterocyclic quaternary phosphonium salts.

Heterocyclic Quaternary Phosphonium Salts (HQPS) have emerged as promising chemicals for organic synthesis and medicinal chemistry. However, the present synthetic methodology of this type of compound is still limited. Here, we report a deconstructive reorganization strategy based on Brønsted acid-mediated tandem 1,4 addition/intramolecular cyclization of triphenylphosphine derivatives and generated -AQMs for the first time.

A Eu(iii) metal-organic framework based on anthracenyl and alkynyl conjugation as a fluorescence probe for the selective monitoring of Fe and TNP.

In this work, a luminescent metal-organic framework (Eu-MOF {[EuL(μ-OH)(HO)]·HO} ) was constructed by a solvothermal method with a linear organic ligand L (10-[(2-amino-4-carboxyl-phenyl)ethynyl]anthracene-9-carboxylic acid) based on anthracene and alkyne groups and using Eu as the metal center. The MOF exhibits a stable UiO-66 crystal structure, and a six-core cluster twelve-linked secondary structural unit was successfully synthesized using 2-fluorobenzoic acid as a modulator, forming a classical fcu topology. Moreover, it exhibits good chemical stability.

Di-, tri- and tetraphosphine-substituted Fe/Se carbonyls: synthesis, characterization and electrochemical properties.

The active sites of [FeFe]-hydrogenase promoted by Fe/E (E = S, Se) clusters have attracted considerable interest due to their significance in understanding the interconversion of hydrogen with protons and electrons. As an extension of the study on Fe/Se clusters related to H-cluster model compounds of [FeFe]-hydrogenase, a series of tertiary phosphine substituted Fe/Se carbonyls were successfully prepared. The treatment of Fe(μ-SePh)(CO) (A) and excess PR resulted in the ferrous bis(selenolate) carbonyls Fe(SePh)(CO)(PR) (PR = PPhMe, 1; PMe, 2) in moderate yields.

Optimal Formula of Angelica sinensis Ameliorates Memory Deficits in β-amyloid Protein-induced Alzheimer's Disease Rat Model.

Objective: Angelica (A.) sinensis is used as a traditional medical herb for the treatment of neurodegeneration, aging, and inflammation in Asia. A.

Novel triorganotin complexes based on phosphonic acid ligands: Syntheses, structures and in vitro cytostatic activity.

Six novel organotin phosphonate complexes, [(MeSn)(HL)]1, [(MeSn)(HL)]2, [(MeSn)L(HO)]3, [(PhSn)(HL)]4, [(PhSn)L]5 and [(PhSn)L]6, derived from phosphonic acid ligands [NaHL = 1-CHOPO(OH)Na, HL = 1-CHPO(OH), HL = 2-CHPO(OH)], have been synthesized and characterized by elemental analysis, FT-IR, NMR (H, C, P and Sn) spectroscopy and X-ray crystallography. The structural analysis reveals that complexes 1 and 5 display 1D infinite zig-zag chain structures, and complex 2 shows 1D right-handed helical chain structure, while complex 3 displays 1D left-handed helical chain structure. Complexes 4 and 6 are 24-membered macrocyclic rings interconnected by P, O and Sn atoms.

Visible-Light-Promoted Cascade Radical Cyclization: Synthesis of Chroman-4-ones and Dihydroquinolin-4-ones.

A novel visible-light photoredox catalysis protocol for the effective and efficient synthesis of 3-substituted chroman-4-ones and 2,3-dihydroquinolin-4(1)-ones via tandem radical addition/cyclization of alkenyl aldehydes has been described. This reaction features a broad substrate scope, mild reaction conditions, and good functional group tolerance character.

Lewis Base-Catalyzed [4 + 3] Annulation of ortho-Quinone Methides and MBH Carbonates: Synthesis of Functionalized Benzo[ b]oxepines Bearing Oxindole Scaffolds.

A novel Lewis base-catalyzed [4 + 3] annulation process for the construction of benzo[ b]oxepine scaffolds has been developed. 1,4-Diazabicyclo[2.2.

Lewis Acid Catalyzed Tandem 1,4-Conjugate Addition/Cyclization of in Situ Generated Alkynyl o-Quinone Methides and Electron-Rich Phenols: Synthesis of Dioxabicyclo[3.3.1]nonane Skeletons.

A versatile Lewis acid catalyzed tandem cyclization of in situ generated alkynyl o-quinone methides ( o-AQMs) with electron-rich phenols has been developed on the basis of the mode involving an intermolecular 1,4-conjugate addition/6-endo cyclization/1,3-aryl shift/intramolecular 1,4-conjugate addition cascade. This reaction provides a new method for expeditious assembly of synthetically and biologically interesting tetracyclic bridged dioxabicyclo[3.3.

Metal-Free One-Pot Synthesis of 3-Phosphinoylbenzofurans via Phospha-Michael Addition/Cyclization of H-Phosphine Oxides and in Situ Generated ortho-Quinone Methides.

A novel metal-free one-pot protocol for the effective and efficient synthesis of 3-phosphinoylbenzofurans via a phospha-Michael addition/cyclization of H-phosphine oxides and in situ generated ortho-quinone methides is described. Based on the expeditious construction of C(sp)-P bonds, asymmetric synthesis of optically pure 3-phosphinoylbenzofurans containing chiral P-stereogenic center has also been probed by using chiral R-(-)-menthyl phenylphosphine oxide.

A novel octa-nuclear 32-membered zirconocene macrocycle based on the aromatic selenite.

A novel macrocyclic zirconocene(iv) aromatic selenite [(CpZr)L]·2(CpZr(μ-O)Cl) (complex 1) (Cp = cyclopentadienyl anion; L = 4-fluorobenzeneseleninic acid) was prepared by the reaction of bis(cyclopentadienyl)zirconium dichloride with 4-fluorobenzeneseleninic acid and characterized by elemental analysis, infrared spectroscopy, H, C NMR spectroscopy, ESI-MS, XRD and X-ray diffraction. The structure analysis shows that complex 1 is a centrosymmetric 32-membered macrocycle containing an eight-nuclear zirconocene. In this complex, the 4-fluorobenzeneseleninic acid ligands adopt bidentate mode in coordinating to zirconium, which play a bridging role in the formation of a macrocycle.

Syntheses, structures and anti-tumor activity of four new organotin(iv) carboxylates based on 2-thienylselenoacetic acid.

With the 2-thienylselenoacetic acid ligand, four new organotin complexes, [Me3Sn(O2CCH2SeC4H3S-o)]n (), [(Ph3Sn)6(O2CCH2SeC4H3S-o)6] (), [(Me2Sn)4(μ3-O)2(O2CCH2SeC4H3S-o)4] (), and [(PhSn)6(μ3-O)6(O2CCH2SeC4H3S-o)6] (), have been synthesized and characterized by X-ray crystallography, elemental analysis, FT-IR and NMR ((1)H, (13)C, and (119)Sn) spectroscopy. The structure analysis indicates that complex adopts a 1D infinite zig-zag chain structure, while complex shows a centrosymmetric hexanuclear 24-membered macrocycle. In contrast, complex and complex display ladder and drum structures, respectively.

Heparanase mRNA and Protein Expression Correlates with Clinicopathologic Features of Gastric Cancer Patients: a Meta- analysis.

Background: Heparanase is believed to be involved in gastric carcinogenesis. However, the clinicopathologic features of gastric cancer with high heparanase expression remain unclear.

Aim: The purpose of this study was to comprehensively and quantitatively summarize available evidence for the use of heparanase mRNA and protein expression to evaluate the clinicopathological associations in gastric cancer in Asian patients by meta-analysis.

The prevalence and incidence of Parkinson's disease in China: a systematic review and meta-analysis.

Parkinson's disease (PD) is a chronic neurodegenerative disorder affecting older individuals. There is inconsistent evidence about the prevalence and incidence of PD in China at present. The aim of the meta-analysis was to estimate the prevalence and incidence of PD and its relation to age, gender, and stage in China.

Bis(4,6-dimethyl-pyrimidine-2-thiol-ato)dimethyl-tin(IV).

The asymmetric unit of the title complex, [Sn(CH(3))(2)(C(6)H(7)N(2)S)(2)], contains two independent mol-ecules with similar configurations. In each, the Sn(IV) cation is coordinated by two methyl and two 4,6-dimethyl-pyrimidine-2-thiol-ate anions in a distorted SnS(2)C(2) tetra-hedral geometry. In the two mol-ecules, the S-Sn-S bond angles are 87.

catena-Poly[[(3-methyl-sulfanyl-1,2,4-thia-diazole-5-thiol-ato)sodium]di-μ-aqua-κO:O].

The crystal structure of the title compound, [Na(C(3)H(3)N(2)S(3))(H(2)O)(2)](n), features polymeric chains made up of O⋯O edge-shared NaSN(H(2)O)(4) units running along the b axis. The Na(+) ion and all non-H atoms of the thia-diazole ligand lie on a mirror plane.

Human herpesvirus-6-specific interleukin 10-producing CD4+ T cells suppress the CD4+ T-cell response in infected individuals.

Human herpesvirus-6 (HHV-6) infection normally persists for the lifetime of the host and may reactivate with immunosuppression. The mechanism behind HHV-6 latent infection is still not fully understood. In this study, we observed that decreased proliferation of CD4+ T cells and PBMCs but not CD8+ T cells from HHV-6-infected individuals was stimulated with HHV-6-infected cell lysates.