Iterative SuFEx approach for sequence-regulated oligosulfates and its extension to periodic copolymers.

The synthesis of sequence-regulated oligosulfates has not yet been established due to the difficulties in precise reactivity control. In this work, we report an example of a multi-directional divergent iterative method to furnish oligosulfates based on a chain homologation approach, in which the fluorosulfate unit is regenerated. The oligosulfate sequences are determined by high resolution mass spectrometry of the hydrolyzed fragments, and polysulfate periodic copolymers are synthesized by using oligomeric bisfluorosulfates in a bi-directional fashion.

Direct F-Fluorosulfurylation of Phenols and Amines Using an [F]FSO Transfer Agent Generated .

We report the direct radiofluorosulfurylation method for the synthesis of F-labeled fluorosulfuryl derivatives from phenols and amines using an [F]FSO transfer agent generated . Nucleophilic radiofluorination is achieved even in a hydrous organic medium, obviating the need for azeotropic drying and the use of cryptands. This unprecedented, operationally simple isotopic functionalization facilitates the reliable production of potential radiotracers for positron emission tomography, rendering facile access to SuFEx radiochemistry.

Reversible Near-Infrared Fluorescence Photoswitching in Aqueous Media by Diarylethene: Toward High-Accuracy Live Optical Imaging.

Fluorescence imaging is an indispensable tool in modern biological research, allowing simple and inexpensive color-coded visualizations of real-time events in living cells and animals, as well as of fixed states of ex vivo specimens. The accuracy of fluorescence imaging in living systems is, however, impeded by autofluorescence, light scattering, and limited penetration depth of light. Nevertheless, the clinical use of fluorescence imaging is expected to grow along with advances in imaging equipment, and will increasingly demand high-accuracy probes to avoid false-positive results in disease detection.

Late-Stage F/F Isotopic Exchange for the Synthesis of F-Labeled Sulfamoyl Fluorides.

Synthesis of sulfamoyl [F]fluorides has been a challenging topic owing to the inefficient nucleophilic radiofluorination of sulfamoyl derivatives. Herein, we report an F/F isotopic exchange approach to synthesize various sulfamoyl [F]fluorides, otherwise inaccessible via direct synthesis from amines, with high radiochemical yields up to 97% (30 examples). This late-stage labeling protocol offers an efficient route to yield functionalized molecules by diversifying the chemical library possessing sulfamoyl functionalities through nucleophilic F incorporation within nitrogen-containing sulfur(VI) frameworks.

Synthesis of F-Labeled Aryl Fluorosulfates via Nucleophilic Radiofluorination.

Sulfuryl fluoride gas is a key reagent for SOF transfer. However, conventional SOF transfer reactions have limited F-radiochemistry translation, due to the inaccessibility of gaseous [F]SOF. Herein, we report the first SOF-free synthesis of aryl [F]fluorosulfates from both phenolic and isolated aryl imidazylate precursors with cyclotron-produced F.

Early Colon Cancer Recurring as Liver Metastasis without Local Recurrence Three Years after Complete Endoscopic Mucosal Resection.

Early colon cancer is defined as colon cancer that invades mucosal or submucosal layer regardless of lymph node invasion. Endoscopic mucosal resection can effectively remove early colon cancer which has no lymph node metastasis. Especially, pedunculated polyp has higher complete resection rate and lower recurrence rate that rarely needs additional surgical treatment than sessile polyp.

IgG4-Related Disease with Esophageal Involvement.

We report the case of a 56-year-old man who presented with dysphagia and weight loss. An esophagoduodenoscopy revealed a severe esophageal stricture in the distal esophagus. After surgical resection, the final pathologic analysis revealed that the tumor was comprised of benign-appearing fibroinflammatory cells with an increase and predominance of IgG4-positive plasma cells.

Annulative π-Extension of Unactivated Benzene Derivatives through Nondirected C-H Arylation.

Annulative π-extension chemistry provides a concise synthetic route to polycyclic arenes. Herein, we disclose a nondirected annulation approach of unactivated simple arenes. The palladium-catalyzed 2-fold C-H arylation event facilitates tandem C-C linkage relays to furnish fully benzenoid triphenylene frameworks using cyclic diaryliodonium salts.

Nickel-Catalyzed Azide-Alkyne Cycloaddition To Access 1,5-Disubstituted 1,2,3-Triazoles in Air and Water.

Transition-metal-catalyzed or metal-free azide-alkyne cycloadditions are methods to access 1,4- or 1,5-disubstituted 1,2,3-triazoles. Although the copper-catalyzed cycloaddition to access 1,4-disubstituted products has been applied to biomolecular reaction systems, the azide-alkyne cycloaddition to access the complementary 1,5-regioisomers under aqueous and ambient conditions remains a challenge due to limited substrate scope or moisture-/air-sensitive catalysts. Herein, we report a method to access 1,5-disubstituted 1,2,3-triazoles using a CpNi/Xantphos catalytic system.

A palladium and gold catalytic system enables direct access to O- and S-linked non-natural glyco-conjugates.

Here we report a straightforward cross-coupling method for the synthesis of non-natural glycoamino acids from alkyne-bearing monosaccharides and p-iodophenylalanine. Pd/Au-catalyzed Sonogashira coupling is tolerant to both O- and S-glycosides without any epimerization. In addition, no racemization of the amino acid was observed allowing direct access to the homogeneous glyco-conjugate in a single step.

A Novel Chemotherapeutic Agent to Treat Tumors with DNA Mismatch Repair Deficiencies.

Impairing the division of cancer cells with genotoxic small molecules has been a primary goal to develop chemotherapeutic agents. However, DNA mismatch repair (MMR)-deficient cancer cells are resistant to most conventional chemotherapeutic agents. Here we have identified baicalein as a small molecule that selectively kills MutSα-deficient cancer cells.

Long-term results of spinal cord injury therapy using mesenchymal stem cells derived from bone marrow in humans.

Background: Although the transplantation of mesenchymal stem cells (MSCs) after spinal cord injury (SCI) has shown promising results in animals, less is known about the effects of autologous MSCs in human SCI.

Objective: To describe the long-term results of 10 patients who underwent intramedullary direct MSCs transplantation into injured spinal cords.

Methods: Autologous MSCs were harvested from the iliac bone of each patient and expanded by culturing for 4 weeks.