Cesium Amide-Catalyzed Selective Deuteration of Benzylic C-H Bonds with D2 and Application for Tritiation of Pharmaceuticals.

Hydrogen isotope exchange (HIE) represents one of the most attractive labeling methods to synthesize deuterium- and tritium-labeled compounds. Catalytic HIE methods that enable site-selective C-H bond activation and exchange labeling with gaseous isotopes D2 and T2 are of vital importance, in particular for high-specific-activity tritiation of pharmaceuticals. As part of our interest in exploring s-block metals for catalytic transformations, we found CsN(SiMe3 )2 to be an efficient catalyst for selective HIE of benzylic C-H bonds with D2 gas. The reaction proceeds through a kinetic deprotonative equilibrium that establishes an exchange pathway between C-H bonds and D2 gas. By virtue of multiple C-H bonds activation and high activity (isotope enrichment up to 99 %), the simple cesium amide catalyst provided a very powerful and practically convenient labeling protocol for synthesis of highly deuterated compounds and high-specific-activity tritiation of pharmaceuticals.

Optimal Catheter Ablation Strategy for Patients with Persistent Atrial Fibrillation and Heart Failure: A Retrospective Study.

The optimal catheter ablation (CA) strategy for patients with persistent atrial fibrillation (PeAF) and heart failure (HF) remains uncertain. Between 2016 and 2020, 118 consecutive patients with PeAF and HF who underwent the CA procedure in two centers were retrospectively evaluated and divided into the pulmonary vein isolation (PVI)-only and PVI + additional ablation groups. Transthoracic echocardiography (TTE) was performed at baseline, one month, and 12 months after the CA procedure. The HF symptoms and left ventricular ejection fraction (LVEF) improvements were analyzed. Fifty-six patients underwent PVI only, and 62 patients received PVI with additional ablation. Compared with the baseline, a significant improvement in the LVEF and left atrial diameter postablation was observed in all patients. No significant HF improvement was detected in the PVI + additional ablation group than in the PVI-only group (74.2% vs. 71.4%, P = 0.736), but the procedure and ablation time were significantly longer (137.4 ± 7.5 vs. 123.1 ± 11.5 min, P = 0.001). There was no significant difference in the change in TTE parameters and the number of rehospitalizations. For patients with PeAF and HF, CA appears to improve left ventricular function. Additional ablation does not improve outcomes and has a significantly longer procedure time. Trial registration number is as follows: ChiCTR2100053745 (Chinese Clinical Trial Registry; https://www.chictr.org.cn/index.aspx).

[Isolation, purification and identification of polysaccharides from Gynura divaricata].

The purpose of this study was to isolate and purify polysaccharide from Gynura divaricata and analyze its monosaccharide composition. A water-soluble crude polysaccharide was obtained by hot water extraction, ethanol precipitation and deproteinization after degreasing. The crude polysaccharide then purified with DEAE-Sepharose Fast Flow column chromatography and dialysis. The monosaccharide composition and structure were analyzed by HPLC, UV spectrophotometer and 1H-NMR. The results showed that the purity and molecular weight of GDPS-2 and GDPS-3 were 87.3%, 2.03 x 10(4) Da and 90.9%, 4.29 x 10(4) Da, respectively. The UV spectrophotometer and 1H-NMR data suggested that glycosidic bond of GDPS-2 and GDPS-3 were a type. Both GDPs-2 and GDPs-3 were homogeneous polysaccharides, and GDPs-2 was mainly composed of glucuronic acid and xylose at a molar ratio of 1.1:0.63. GDPs-3 was mainly composed of rhamnose, glucuronic acid, galactose, xylose and galacturonic acid at a molar ratio of 0.32:6.0:0.21:1.75:4.3.