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A general photoredox-catalyzed intramolecular cyclization was developed for the synthesis of trifluoromethylated heterocyclic compounds. The reaction proceeded smoothly under mild photocatalytic conditions with high functional group tolerance, allowing the preparation of oxygen-, sulfur-, or nitrogen-containing heterocycles of different sizes. The broad substrate scope demonstrated the complexity-building potential of the strategy.

The direct oxidative addition of CF3 and H2O to alkynes was achieved with photoredox catalysis to obtain α-trifluoromethyl ketones via rapid enol-keto tautomerization. The reaction exhibits high functional group tolerance and regioselectivity. Heterocycles of various sizes containing CF3 were synthesized from the α-CF3-substituted diketones obtained through the protocol, thereby demonstrating the versatile applicability of the method. Mechanistic studies of the reaction with isotopes provided insight into the reaction pathway.

[Image: see text] Hepatitis B virus (HBV) remains a major health concern with 260 million people having been infected globally, and approximately 680,000 deaths have occurred annually from cirrhosis and liver cancer. The modulation of HBV capsid assembly has emerged as a promising therapeutic approach for curing chronic HBV infection. Small-molecule capsid assembly modulators (CAMs) can broadly be classified as heteroaryldihydropyrimidines and sulfamoylbenzamides (SBAs). SBAs are capsid activators that inhibit viral replication by achieving capsid assembly before polymerase encapsulation. Herein, we report a novel series of HBV CAMs based on NVR 3-778, a potent CAM belonging to the SBA class. The lead compound (KR-26556) exhibited improved pharmacological activity and was examined through molecular docking studies.

A general photoredox-catalyzed intramolecular cyclization was developed for the synthesis of trifluoromethylated heterocyclic compounds. The reaction proceeded smoothly under mild photocatalytic conditions with high functional group tolerance, allowing the preparation of oxygen-, sulfur-, or nitrogen-containing heterocycles of different sizes. The broad substrate scope demonstrated the complexity-building potential of the strategy.

The Pohang Accelerator Laboratory (PAL) is developing a self amplification of spontaneous emission (SASE) based free electron laser (FEL) for X-ray coherent photon sources. The PAL developed a prototype undulator that had a 5.0 m magnetic length and a 7.2 mm minimum gap at a magnetic field of ∼0.908 T. The PAL has constructed an undulator field measurement facility to confirm the field qualities of the X-ray free electron laser (XFEL) undulators in the assembly building. Two field measurement benches which included a Hall probe scanner, a flip coil and a stretched wire system were installed and their performances were evaluated. This paper describes the field measurement facility and presents the performance test results of the two benches.

A new photoredox-catalyzed chlorotrifluoromethylation reaction of internal arylalkynes under mild conditions using visible light has been developed. The reactions proceed with high levels of regio- and stereoselectivity and utilize commercially available CF3SO2Cl as both the CF3 and Cl source. In the mechanistic pathway for this process, generation of the CF3 radical and chloride ion occurs by Ir(ppy)3-photocatalyzed reductive decomposition of CF3SO2Cl. The synthetically important trifluoromethyl-substituted vinyl chlorides produced in this process can be readily transformed to 1,1-bis-arylalkenes by using Suzuki coupling.

Air-stable azomethine ylides with an unusual pattern of charge distribution were efficiently prepared via the rhodium-catalyzed reaction between pyridines and 1-sulfonyl-1,2,3-triazoles. This reaction allowed for the first example of the catalytic multicomponent [5 + 2] cycloaddition reactions, thus resulting in the formation of biologically active 1,4-diazepine compounds.

This paper describes the result of overall studies from development to characterization of undulator radiation. After three years of upgrading, PLS-II [1, 2] has been operating successfully since 21st March 2012. During the upgrade, we developed and installed an in-vacuum undulator (IVU) that generates brilliant X-ray beam. The IVU with 3 GeV electron beam generates undulator radiation up to ~ 21 keV using 11th higher harmonic. The characterizations of the undulator radiation at an X-ray beam line in PLS-II agreed well with the simulation. Based on this performance demonstration, the in-vacuum undulator is successfully operating at PLS-II., Comment: ICABU2015 conference (in Korea)

In the storage ring of PLS-II, we reduced mechanical displacement of electron beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The orbit feedback system intends that the electron beam pass through the center of the BPM, so to provide stable photon beam into beamlines the BPM pickup itself must be stable to sub-micrometer precision. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report the thermo-mechanical analysis and displacement measurements of BPM pickups after the improvements., Comment: 12 pages, 5 figures, conference

The 100 MeV PEFP (Proton Engineering Frontier Project) proton linac has two proton beam extraction lines for user experiment. Each extraction line has 5 beamlines and has 2.5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beam-lines, An AC switching magnet is excited by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ± 350A, 2.5 Hz programmable current step output. The power supply is employed IGBT modules and has been controlled by a Digital Signal Processor (DSP). This paper describes the design and test results of the power supply.

The PEFP (Proton Engineering Frontier Project) proton linac is designed to have two proton beam extraction lines at the 20-MeV and 100-MeV end. The 20-MeV extraction line is branched out into 5 beamlines by using the switching magnet. The magnet bends the proton beam by +20, +10, 0, -10, -20 degrees, respectively, and has an AC frequency of 2.5 Hz with a programmable ac power supply. It employs an H-shape, 0.45 T magnetic fields, 500 mm effective length, and 50 mm pole gap. Laminated steel of 0.5 mm reduces the eddy currents in the yoke, but some heat radiation from the stainless steel of vacuum chamber is inevitable. This paper presents the magnet specification and primary design.