Photoinduced Copper-Catalyzed Monofluoroalkylation of Terminal Alkynes to Propargylic Fluorides

A photoinduced copper-catalyzed strategy for the monofluoroalkylation of alkynes with readily available monofluoroalkyl triflates was developed. It provides a new protocol to access valuable propargyl fluoride compounds via C-C bond formation by avoiding the use of highly toxic fluorination reagents. This reaction proceeded under mild conditions to afford propargyl monofluorides in moderate to high yields. Preliminary mechanistic studies reveal that a ligand-matched alkynyl copper complex might be the key photoactive substance.

Iron-catalyzed remote functionalization of inert C(sp3)-H bonds of alkenes via 1,n-hydrogen-atom-transfer by C-centered radical relay

As an alternative approach to traditional C-H activation that often involved harsh conditions, and vicinal or primary C-H functionalization, radical relay offers a solution to these long-held problems. Enabled by 1,n (n = 5, 6)-hydrogen atom transfer (HAT), we use a most prevalent moiety, alkene, as the precursor to an sp³ C-centered radical to promote selective cleavage of inert C(sp³)-H bonds for the generation of azidotrifluoromethylated molecules. Mild conditions, broad scope and excellent regioselective control (>20 : 1) are observed in the reactions. Deuterium labelling studies disclose the kinetic characteristics of the transformations and verify a direct 1,n-HAT pathway. The key to this C-centered radical relay is that iron plays a dual role as a radical initiator and terminator to incorporate the azide functionality through radical oxidation via azido-ligand-transfer. The methods and the later derivatization promise expeditious synthesis of CF₃-containing organic azides, γ-lactam and triazoles that are widely used in designing new fluorescent tags and functional materials.

Nickel-catalyzed monofluoromethylation of (hetero)aryl bromides via reductive cross-coupling

Nickel-catalyzed direct monofluoromethylation of (hetero)aryl bromides with industrial raw material BrCH₂F by reductive cross-coupling has been developed.

Nickel-Catalyzed Reductive Cross-Coupling of Aryl Halides with Monofluoroalkyl Halides for Late-Stage Monofluoroalkylation

A combinatorial nickel-catalyzed monofluoroalkylation of aryl halides with unactivated fluoroalkyl halides by reductive cross-coupling has been developed. This method demonstrated high efficiency, mild conditions, and excellent functional-group tolerance, thus enabling the late-stage monofluoroalkylation of diverse drugs. The key to success was the combination of diverse readily available bidentate and monodentate pyridine-type nitrogen ligands with nickel, which in situ generated a variety of readily tunable catalysts to promote fluoroalkylation with broad scope with respect to both coupling partners. This combinatorial catalysis strategy offers a solution for nickel-catalyzed reductive cross-coupling reactions and provides an efficient way to synthesize fluoroalkylated druglike molecules for drug discovery.

Serum matrix metalloproteinases-3 levels in patients with ankylosing spondylitis

Cumulated evidence indicates that matrix metalloproteinase-3 (MMP-3) is significantly involved in cancer progression. Recent studies yielded conflicting results regarding the association between serum MMP-3 and ankylosing spondylitis (AS). To clarify this correlation, we performed a meta-analysis. Potential relevant studies were identified by searching the following databases: PubMed, Embase, CINAHL, Science Citation Index database, the Cochrane Library, Current Contents Index, Chinese Biomedical, the Chinese Journal Full-Text, and the Weipu Journal. Data from eligible studies were extracted and included into the meta-analysis using a random-effect model. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were used to assess the association between serum MMP-3 levels and AS. Thirteen case-control studies, including 707 AS cases and 442 healthy controls, were selected for the meta-analysis. The results indicate a significantly higher serum MMP-3 level in patients with AS than that in the controls (cases vs controls: SMD = 1.31, 95%CI = 0.84-1.78, P < 0.001). Ethnicity-subgroup analysis indicated a higher MMP-3 level in Asian and Caucasian patients with AS (all P < 0.05). This meta-analysis indicates that increased serum MMP-3 level correlates with the development of AS, suggesting that MMP-3 may present a clinical value in reflecting the progression of AS. Further larger sample size studies are warranted.

Effect of exercise training on renal function and renal aquaporin-2 expression in rats with chronic heart failure

1. Chronic heart failure (CHF) is often accompanied by renal dysfunction. Exercise training may relieve the symptomatic burden and improve the overall prognosis of CHF. In the present study, the effects of exercise training on renal function and renal aquaporin (AQP)-2 expression in CHF rats were examined to determine whether exercise training could relieve renal dysfunction in CHF rats. 2. Male Sprague-Dawley rats were divided into three groups: sham, sedentary CHF (Sed-CHF) and exercise training CHF (Ex-CHF) groups. Cardiorenal function was assessed in each group by haemodynamic measurement and ultraviolet spectrophotometry. Pathological changes in cardiac and renal tissues were evaluated histologically and the collagen volume fraction (CVF) was calculated. The expressions of AQP-2 and β-tubulin were determined by western blotting and immunohistochemistry. 3. The Sed-CHF rats were found to have increased left ventricular end-diastolic pressure (LVEDP) and CVF in the heart compared with sham rats. Exercise training decreased LVEDP and CVF values in Ex-CHF rats. The Sed-CHF rats were found to have increased serum levels of creatinine (sCr), blood urea nitrogen (BUN) and arginine vasopressin (AVP), as well as increased CVF in the kidney, compared with sham rats. Exercise training decreased levels of sCr, BUN, AVP and CVF in Ex-CHF rats. Moreover, exercise training decreased AQP-2 and β-tubulin protein expression in the kidney of CHF rats. 4. The results suggest that exercise training can significantly improve the renal dysfunction in CHF rats and that the underlying mechanism may be related to water reabsorption and preventing changes to the cytoskeleton.

Identifying magnetic anisotropy of the topological surface state of Cr(0.05)Sb(1.95)Te(3) with spin-polarized STM

The surface magnetic property plays a key role in determining magnetic related quantum phenomena of magnetic topological insulators. Using spin-polarized scanning tunneling microscopy, we investigate the surface magnetism and anisotropy of a Cr doped topological insulator: Cr(0.05)Sb(1.95)Te(3). It is found that the topological surface state of Cr(0.05)Sb(1.95)Te(3) is spin polarized in the surface plane while the bulk shows a ferromagnetism with an out-of-plane easy axis. The upper and lower branch of the helical Dirac cone harbors the opposite spin polarization and the polarization at the Dirac point is zero. Our results show the complexity of surface magnetism of magnetic doped topological insulators.

The effects of Buyang Huanwu Decoction on hemorheological disorders and energy metabolism in rats with coronary heart disease

ETHNOPHARMACOLOGICAL RELEVANCE

Buyang Huanwu Decoction (BYHWD), a traditional Chinese medicine (TCM) formula, has been recognized as a clinical treatment for coronary heart disease (CHD) with qi deficiency and blood stasis syndrome. The effects of BYHWD on hemorheological disorders and energy metabolism in CHD with qi deficiency and blood stasis syndrome are still unclear.

AIM OF THE STUDY

To investigate whether the ameliorative effects of BYHWD on CHD rats with qi deficiency and blood stasis syndrome are associated with the regulation of hemorheological disorders and energy metabolism.

MATERIALS AND METHODS

The rats were lavaged with 25.68, 12.84 and 6.42 g/kg BYHWD (g weight of mixed crude drugs/kg body weight), respectively, once a day for 21 days. The body weight, exhaustive swimming time and tongue characters were observed and recorded. The whole blood viscosity and plasma viscosity were determined by hematology analyzer. The level of fibrinogen (Fbg) in plasma was determined by using Fbg assay kit. The platelet aggregation induced by adenosine diphosphatase was measured by semi-automatic whole blood platelet analyzer. The level of blood glucose (BG) was determined by LifeScan. The activity of Na(+)-K(+)-ATPase in heart tissues was detected by spectrophotometer.

RESULTS

BYHWD improved the exterior signs of qi deficiency and blood stasis syndrome in rats with CHD, including the body weight, exhaustive swimming time and tongue quality. The whole blood viscosity in rats treated with 25.68 g/kg BYHWD decreased at the shear rate of 10s(-1) (P<0.05) and the plasma viscosity decreased in rats treated with 25.68 and 12.84 g/kg BYHWD (P<0.05). The plasma Fbg level and the platelet aggregation decreased in rats treated with 25.68 g/kg BYHWD (P<0.01). The results also revealed that the BG level decreased and the Na(+)-K(+)-ATPase activity in heart tissues increased in rats treated with 25.68 and 12.84 g/kg BYHWD (P<0.01).

CONCLUSION

The results suggest that the ameliorative effects of BYHWD on CHD rats with qi deficiency and blood stasis syndrome are mediated by the improvement of hemorheological disorders and energy metabolism.