Radical <i>ipso</i>-Substitution of a Carbon–Fluorine Bond Leading to Fluoro-7-azaindolines and Fluoro-7-azaindoles

Rare examples of a synthetically useful radical <i>ipso</i>-substitution of a carbon–fluorine bond are reported, leading to highly functionalized 5,6-difluoro-7-azaindolines. An unexpected hydrogen atom translocation and fragmentation with loss of molecular nitrogen and formation of a nitrile were observed in the case of an <i>N</i>-benzyl-tetrazole derivative

Expedient Approach to Novel N‑Unprotected Bicyclic Azapyrimidine and Pyridine Structures

A direct route to novel bicyclic <i>N</i>-unprotected azapyrimidine structures including fused five-, six-, and seven-membered rings is described involving radical addition and cyclization of xanthates; this approach could be partially extended to pyridines

Base-Promoted Protodeboronation of 2,6-Disubstituted Arylboronic Acids

Facile based promoted deboronation of electron-deficient arylboronate esters was observed for arylboronates containing two ortho electron-withdrawing group (EWG) substituents. Among 30 representative boronates, only the diortho-substituted species underwent facile C–B fission in aqueous basic conditions (200 mM hydroxide). These results provide fundamental insight into deboronative mechanisms with implications for cross-coupling reactions, regioselective deuteration/tritiation for isotopic labeling, and the design of new ¹⁸F-trifluoroborate radioprosthetics

Desulfonylative Radical Ring Closure onto Aromatics. A Modular Route to Benzazepin-2-ones and 5-Arylpiperidin-2-ones

Adducts from the intermolecular radical addition of <i>N</i>-xanthylacetyl-<i>N</i>-methanesulfanilides to Boc-protected allylamine undergo ring closure with loss of a methanesulfonyl radical to give benzazepin-2-ones. Upon deprotection and exposure to triethylamine, these compounds rearrange into 5-aryl-2-piperidones. This approach also represents a useful route to benzazepin-2-ones unsubstituted on the nitrogen atom of the azepinone ring

Imaging in a 3-year-old boy with PA-VSD.

<p>3D Volume-rendered image with electronic dissection, which remove contrast from the cardiac chambers, shows the defect (*) in ventricle septum (VS) and the overriding aorta (<50%). AAo indicates ascending aorta.</p

The diagnostic algorithm used for patients with PA-VSD.

<p>The diagnostic algorithm used for patients with PA-VSD.</p

MDCT in a 4-year-old boy with PA-VSD.

<p>(a) Axial CT shows the patients has patent ductus arteriosus(*). Some MAPCAs (white arrow) from the descending aorta (DAo) to the right lung. (b) Axial CT demonstrates good-sized right pulmonary artery (RPA) and left pulmonary artery(LPA). The orifice of a MAPCA (#) is depicted clearly. (c) 3D Volume-rendered image (posterior view) shows a MAPCA (white arrowhead) from the descending aorta to the right lung.</p

NiPS₃ Nanosheet–Graphene Composites as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

Developing new electrocatalysts is essentially important for efficient water splitting to produce hydrogen. Two-dimensional (2D) materials provide great potential for high-performance electrocatalysts because of their high specific surface area, abundant active edges, and tunable electronic structure. Here, we report few-layer NiPS₃ nanosheet–graphene composites for high-performance electrocatalysts for oxygen evolution reaction (OER). The pure NiPS₃ nanosheets show an overpotential of 343 mV for a current density of 10 mA cm^–2, which is comparable to that for IrO₂ and RuO₂ catalysts. More importantly, the NiPS₃ nanosheet–graphene composites show significantly improved OER activity due to the synergistic effect. The optimized composite shows a very low overpotential of 294 mV for a current density of 10 mA cm^–2, 351 mV for a current density of 100 mA cm^–2, a small Tafel slope of 42.6 mV dec^–1, and excellent stability. These overall performances are far better than those of the reported 2D materials and even better than those of many traditional materials even at a much lower mass loading of NiPS₃

Activating TiO₂ Nanoparticles: Gallium-68 Serves as a High-Yield Photon Emitter for Cerenkov-Induced Photodynamic Therapy

The classical photodynamic therapy (PDT) requires external light to activate photosensitizers for cancer treatment. However, limited tissue penetration of light has been a long-standing challenge for PDT to cure malignant tumors in deep tissues. Recently, Cerenkov radiation (CR) emitted by radiotracers such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) has become an alternative and promising internal light source. Nevertheless, fluorine-18 (F-18) only releases 1.3 photons per decay in average; consequently, injection dose of F-18 goes beyond 10–30 times more than usual to acquire therapeutic efficacy because of its low Cerenkov productivity. Gallium-68 (Ga-68) is a favorable CR source owing to its ready availability from generator and 30-time higher Cerenkov productivity. Herein, we report, for the first time, the use of Ga-68 as a CR source to activate dextran-modified TiO₂ nanoparticles (D-TiO₂ NPs) for CR-induced PDT. Compared with ¹⁸F-FDG, ⁶⁸Ga-labeled bovine serum albumin (⁶⁸Ga-BSA) inhibited the growth of 4T1 cells and exhibited significantly stronger DNA damage to tumor cells. In vivo studies showed that the tumor growth was almost completely inhibited when tumor-bearing mice were treated with a combination of D-TiO₂ NPs and ⁶⁸Ga-BSA. This study proved that Ga-68 is a more potent radionuclide for PDT than F-18 both in vitro and in vivo offered a promising strategy of using a diagnostic dose of radioactivity to achieve depth-independent cancer therapy without using any external light source

¹⁸F‑Alanine Derivative Serves as an ASCT2 Marker for Cancer Imaging

Amino acids derivative are well established molecular probes for diagnosis of a variety of cancer using positron emission tomography (PET). Recently, boramino acid (BAAs) was found as a prospective molecular platform for developing PET tracer. The objective of this study was to develop a ¹⁸F-labeled alanine derivative through displacing its carboxylate by trifluoroborate as a selective ASCT2 marker for cancer imaging. ¹⁸F-Ala-BF₃ was first evaluated in healthy FVB/N mice <i>in vivo</i>, exhibiting rapid renal clearance with almost negligible uptake in stomach (1.53 ± 0.31%ID/g). Notable uptake was observed in thyroid (3.71 ± 0.49%ID/g, 40 min post injection), of which the uptake was significantly inhibited by co-injection with natural L-alanine. In addition, we further established ¹⁸F-Ala-BF₃ on a human gastric cancer cell (BGC-823) xenografts bearing mouse model. Dynamic PET-CT scan revealed the optimal time window for tumor imaging, it was between 40 and 60 min post injection, when the BGC-823 xenografts uptake was 5.49 ± 1.47%ID/g (<i>n</i> = 4), and the tumor-to-stomach, tumor-to-blood, tumor-to-muscle, and tumor-to-brain ratios were 3.27 ± 1.53, 3.80 ± 1.48, 3.47 ± 1.48, and 6.20 ± 1.47, respectively