Synthesis of Homoallylic Amines by Radical Allylation of Imines with Butadiene under Photoredox Catalysis.

Ionic (2 e- ) nucleophilic addition of allylmetal regents to imines dominates the synthesis of homo-allyl amine; however, single electron (1 e- ) mediated imine allylation with feedstocks butadiene as an alternative allyl source remains unexplored. In this work, we report a conceptually different radical-radical cross-coupling strategy for the synthesis of a homoallyl amine between an α-amino alkyl radical and a transient allylic radical. This metal-free method provided a novel approach for the synthesis of homoallylic amines (>80 examples) from readily available materials with excellent regioselectivity and exceptional broad functional group compatibility.

Photocatalytic Generation of π-Allyltitanium Complexes via Radical Intermediates.

The addition of π-allylmetal complexes to carbonyls is the most important route to homoallylic alcohols. This study reports the first photocatalytic generation of π-allyltitanium complexes by a radical strategy. This novel strategy enables the three-component allylation of carbonyls with 1,3-butadiene, providing rapid access to valuable homoallylic alcohols (over 60 examples). The exceptional regio- and diastereoselectivity provided by dual photoredox/Ti catalysis is comparable to that of the Cr-catalyzed Nozaki-Hiyama-Kishi allylation reaction.

Asymmetric Total Synthesis of Ieodomycin B.

Ieodomycin B, which shows in vitro antimicrobial activity, was isolated from a marine Bacillus species. A novel asymmetric total synthetic approach to ieodomycin B using commercially available geraniol was achieved. The approach involves the generation of 1,3-trans-dihydroxyl at C-3 and C-5 positions via a Crimmins-modified Evans aldol reaction and a chelation-controlled Mukaiyama aldol reaction of a p-methoxybenzyl-protected aldehyde, as well as the generation of a lactone ring in a deprotection-lactonization one-pot reaction.

Regulating the interface electron distribution of iron-based MOFs through ligand functionalization enables efficient peroxymonosulfate utilization and catalytic performance.

Ligand functionalization is an effective way to endow Metal-organic frameworks (MOF) with versatility for multiple applications by introducing or displaying substituents without changing the origin framework. In this work, the original MIL-101(Fe) was modified by functional groups, including -NH2, -NO2, -CH3, and -Cl substituents. The Bader charge results and electron localization function (ELF) quantitatively indicated that the functional ligands with different properties can regulate the electron structure of transition-metal centers through interface-charge redistribution. Accompanying the higher adsorption and utilization rate of peroxymonosulfate (PMS), more than 96% of acetaminophen (APAP) was degraded with a mineralization rate of 40.17% under the NH2-BDC/PMS system. In terms of mechanism, the amino group not only accelerated the regeneration of Fe(II) via the NCFe electron-transfer path, but also stimulated the appearance of high-valent Fe species. Meanwhile, the degradation pathways of APAP were proposed by integrating the results of liquid chromatograph-mass spectrometry (LC-MS) and Frontier molecular-orbital theory. Finally, the NH2-BDC/PMS system reveals long-term stability, nonselectivity, low biotoxicity as well as secondary pollution for pollutant degradation, which is a considered candidate for further environmental applications.

Photochemical Nozaki-Hiyama-Kishi Coupling Enabled by Excited Hantzsch Ester.

This work reports the first photochemical Nozaki-Hiyama-Kishi coupling enabled by bioinspired Hantzsch ester. The salient feature of this process is that commercially available and low-cost organic photoactive Hantzsch ester can serve as both an electron and a proton donor to reduce Cr/Ni to low-valent species and hydrolyze the CrIII-alkoxy bond, thus bypassing the use of stoichiometric metallic reductants and additives such as TMSCl and Cp2ZrCl2. The mild conditions and operationally easy method showed broad compatibility with various alkenyl triflates and aldehydes, including electron-poor pentafluorobenzaldehyde which failed under previous conditions.

Hyperuricemia as a possible risk factor for abnormal lipid metabolism in the Chinese population: a cross-sectional study.

BACKGROUND: Previous studies have reported that there may be a close relationship between elevated serum uric acid (UA) levels and metabolic syndrome. However, the association between these two factors has not been explored explicitly. Therefore, we carried out this study to investigate the association between UA and lipid profiles. METHODS: A total of 2,482 subjects participated in this cross-sectional study using a multistage stratified sampling method. Lipid profile, glucose metabolism, and other metabolic factors were measured and classified into UA-stratified and age-stratified groups to investigate the relationship between hyperuricemia and metabolic factors. Pearson correlations and logistic regressions were utilized to further explore the association between UA and lipid profile. RESULTS: The individuals aged 18 to 29 years presented with high serum UA concentrations. Moreover, the prevalence of hyperuricemia was higher among men than in women. Furthermore, statistically significant positive correlations were found between UA and serum triglycerides (TG), serum total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-c). Conversely, only high-density lipoprotein cholesterol (HDL-c) was negatively correlated. Moreover, TG group status (1.70≤ TG <2.30 mmol/L) was an independent risk factor for hyperuricemia in both univariate and multivariate models. CONCLUSIONS: This study found significant positive associations between TG, TC, LDL, and UA but an inverse relationship with HDL-c. Thus hyperuricemia may be a risk factor for abnormal lipid metabolism.

Activation of Chromium Catalysts by Photoexcited Hantzsch Ester for Decarboxylative Allylation of Aldehydes with Butadiene.

Metallaphotocatalysis often needs light-absorbing metal-polypyridyl complexes, semiconductors, or organic dyes, which can modify the oxidation state of metal catalysts. Here, we first report that photoexcitation of Hantzsch ester can directly activate chromium reagents through a single-electron transfer process. The synthetic application was demonstrated through a photoredox decarboxylative allylation of aldehydes with feedstock butadiene without exogenous photocatalysts, metallic reductants, or additives.

Visible-light-driven spirocyclization of epoxides via dual titanocene and photoredox catalysis.

We describe the synergistic utilization of titanocene/photoredox dual catalysis driven by visible light for the radical opening/spirocyclization of easily accessible epoxyalkynes. This environmentally benign process uses the organic donor-acceptor fluorophore 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst and Hantzsch ester (HE) as an electron donor instead of stoichiometric metallic reductants. The photocatalytic conditions showed exceptionally high reactivity for the synthesis of privileged and synthetically challenging spirocycles featuring a spiro all-carbon quaternary stereocenter. Cyclic voltammetry (CV) studies suggest that Cp2TiIIICl is the catalytically active species.

Effects of Huatan Tongluo decoction on vascular endothelial growth factor receptor 2 expression in synovial tissues of rats with collagen-induced arthritis.

OBJECTIVE: To determine the therapeutic effect and potential mechanism of Huatan Tongluo decoction on rats with collagen-induced arthritis. METHODS: Forty specific pathogen-free Wistar rats were selected, and 10 were randomly selected as the control (group 1). The remaining rats were injected intradermally with emulsified type II bovine collagen at the tail base and back, followed by a booster 7 d post first immunization. After establishing collagen-induced arthritis (CIA), rats were randomly divided into three groups (n = 10). The rats were treated orally for 30 d as follows: group 1, saline; group 2, model (saline); group 3, tripterygium polyglycoside (TP; 7.81 mg/kg, positive control); group 4, Huatan Tongluo decoction (HTTL; 7.5 g/kg). Body weight, ankle swelling and arthritis index were measured over the course of the study. The rats were sacrificed 30 d after treatment. Morphological changes in the synovium were observed by hematoxylin and eosin staining. Pannus formation and synovial thickness in the left ankle were observed by color Doppler ultrasoundVascular endothelial growth factor (VEGF) and VEGFR2 protein levels were measured by immunohistochemistry. VEGF/VEGFR2 mRNA levels were measured by real-time quantitative polymerase chain reaction. RESULTS: Compared with the model group, a significantly lower arthritis index was observed in the positive control group (P < 0.05) and HTTL group (P < 0.01), after treatment. Both positive control and HTTL reduced intra-articular pannus formation and synovial thickening. Furthermore, VEGF mRNA, and VEGFR2 protein and mRNA levels were significantly downregulated (P < 0.05) in the treatment groups. CONCLUSION: Inhibition of the expression of VEGF and VEGFR2 in synovial tissues and the formation of pannus and synovial hyperplasia may be part of the mechanism of HTTL for relieving the symptoms of rheumatoid arthritis in CIA rats.

Stereoselective total synthesis of (-)-(6S,2'R)-cryptocaryalactone.

We described a novel stereoselective total synthesis of (-)-(6S,2'R)-cryptocaryalactone, a natural product containing syn/anti-6,8-diol/5,6-dihydro-2H-pyran-2-one unit. The approach, which characterised a highly diastereoselective chelation-controlled Mukaiyama aldol reaction of a benzyl-protected aldehyde and a Yamaguchi lactonisation of a δ-hydroxy-trans-α,ß-unsaturated carboxylic acid, is an alternative synthetic strategy towards cryptocaryalactones.