A Visible-Light-Promoted C-H Arylation and Heteroarylation of Uracil Derivatives with Diazoniums in Aqueous Conditions.

The photoredox synthesis of C-5 (hetero)arylated uracil and uridine substrates with the corresponding diazonium salts is described. The coupling proceeds efficiently without protection of the hydroxyls at the ribose or pre-functionalization of the C5 position at the nucleobase. No transition-metal catalyst is used in this transformation, thereby avoiding metal contamination in the final products. The use of water as the medium also eliminates the impurities caused by the use of organic solvents. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of 5-aryl and 5-heteroaryl uracil derivatives Basic Protocol 2: Synthesis of 5-aryl uridine and deoxyuridine uridine derivatives.

Aqueous and Visible-Light-Promoted C-H (Hetero)arylation of Uracil Derivatives with Diazoniums.

Direct C5 (hetero)arylation of uracil and uridine substrates with (hetero)aryl diazonium salts under photoredox catalysis with blue light was reported. The coupling proceeds efficiently with diazonium salts and heterocycles in good functional group tolerance at room temperature in aqueous solution without transition-metal components. A plausible radical mechanism has been proposed.

[Natural Water Chemistry Change in the Surface Water of Chengdu and Impact Factors].

To investigate the impact of megacities on the chemistry of surface waters, monthly sampling and monitoring were conducted in the Chengdu section of the Minjiang and Tuojiang River basin, corresponding to the upper reaches of the Yangtze River since the spring of 2019, including the influent and effluent water samples from 57 sewage treatment plants in Chengdu. All the samples were analyzed for major ions and other water chemistry parameters, and compared with the historical data of the Minjiang and Tuojiang River. The results showed that the Chengdu surface water still presented a natural chemistry with medium-low total dissolved solids(TDS), and calcium bicarbonate chemistry type, which is the natural consequence of the weathering of carbonate rocks in the basin effected by the weathering of silicates and evaporites. The natural water chemistry of the surface waters in Chengdu presented monthly variation, i.e.,the concentration of major ions and TDS was higher in the dry season compared to the wet season, reflecting the variations of point source. Spatially, the concentration of major ions and TDS downstream of the city was higher than those in the upper reaches, and the concentration in the tributary was higher than that in the mainstream, which may reflect urban influence. Further analyses, such as simulation calculations, indicated that urban activities were the major driving factor for the chemistry change in the surface waters in Chengdu, which is evidenced by the significant contribution of the sewage discharge to the elevated Cl- and Na+ and the ratio of hardness/alkalinity>1 from anthropogenic acid gas emissions. A comparison with the water chemistry of the Minjiang and Tuojiang River in the 1960s indicated that, the current Cl-/Na+ ratio has significantly increased, which has been evidenced by a salinization trend. As a megacity nearest to the source of the Yangtze River, the impact of Chengdu on the natural water chemistry of the Yangtze River system and its environmental effects deserves more attention.

Preparation and characterization of V-shaped PS-b-PEO brushes anchored on planar gold substrate through the trithiocarbonate junction group.

Trithiocarbonate group was introduced into the polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymers as the junction of the blocks through RAFT polymerization. Mixed PS and PEO brushes with a V-shape were prepared by anchoring the trithiocarbonate group on the planar gold substrate. The morphology of the V-shaped brushes was characterized by atomic force microscopy (AFM) and the surface composition responsive to solvent treatment was detected by X-ray photoelectron spectroscopy (XPS). Different morphologies were observed for the V-shaped PS-b-PEO brushes, depending on the chain structure and solvent treatment. The highly selective solvent for PEO, ethanol, can intensify or induce microphase separation of the V-shaped brushes, leading to vertical microphase separation. When the V-shaped brushes are treated with the co-solvent, THF, miscible morphology, lateral microphase separation, and vertical microphase separation are observed as the PS block length increases. After treatment with the non-selective poor solvent, cyclohexane, the V-shaped PS(106)-b-PEO(113) brush, exhibits a laterally microphase-separated morphology, but the V-shaped PS(52)-b-PEO(113) and PS(253)-b-PEO(113) brushes are vertically microphase-separated.

Facile fabrication of amphiphilic gold nanoparticles with V-shaped brushes from block copolymers with a trithiocarbonate group as the junction.

Amphiphilic gold nanoparticles grafted with V-shaped brushes (Au-V-brushes) were prepared by grafting a polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymer with a trithiocarbonate group as the junction to the Au surface. The obtained Au-V-brushes were subjected to solubility test and UV-vis, FT-IR, TEM and DLS characterizations. It is found that the Au-V-brushes are soluble in both water and organic solvents. In the common solvent DMF, the size of the Au-V-brushes is about 17 nm, whereas in selective solvents (toluene and water) aggregates of 70-90 nm are formed. Phase transfer of the Au-V-brushes from the water phase into the toluene phase occurs upon addition of Na(2)SO(4) into water and the Au-V-brushes can also transfer from the toluene phase to the interface of toluene and water phases after addition of citric acid in the water phase.

[Effects of Tangxinping Capsule on angiotensin II and its type 1 receptor and myocardial ultrastructure in diabetic rats].

OBJECTIVE: To investigate the protective effects of Tangxinping Capsule, a compound traditional Chinese herbal medicine, on diabetic cardiomyopathy in rats. METHODS: The model of diabetes mellitus was induced by streptozotocin (STZ) injection in rats. And the rats with diabetes mellitus were randomly divided into untreated group, metformin group, captopril group, and low-, medium- and high-dose Tangxinping group; the other ten normal rats were used as normal controls. After eight-week treatment, all rats were sacrificed to detect angiotensin II (Ang II) protein content and angiotensin II type 1 receptor (AT1R) mRNA expression in myocardial tissues by radioimmunoassay and reverse transcription polymerase chain reaction (RT-PCR) respectively. The ultrastructural change in myocardial tissues was detected by transmission electron microscopy. RESULTS: The results of radioimmunoassay and RT-PCR showed that the content of Ang II protein and the expression of AT1R mRNA in myocardial tissue of the untreated group was significantly increased and more than those in normal control (P<0.05, P<0.01). Only the content of Ang II and expression of AT1R mRNA in high-dose Tangxinping group and captopril group were significantly lower than those in the untreated group (P<0.05, P<0.01). The transmission electron microscopy showed that volume of mitochondrion in myocardial tissue in the untreated group was bigger than that in normal control group. Also the volume of mitochondrion was improved in 5 treated groups, but had no significant difference when compared with the untreated group. CONCLUSION: Tangxinping may adjust the disorder of renin-angiotensin system to protect myocardial tissue in rats with cardiomyopathy due to diabetes.