A visible-light-induced tandem radical intramolecular cyclization/arylatiion of quinoxalin-2(1H)-ones with bromodifluoroacetamides is described.This protocol allows efficient access to a variety of valuableα,α-difluoro-y-lactam-fused quinoxalin-2(1H)-ones in moder-ate to good yields under metal-free,mild and redox neutral reaction conditions.This strategy is tolerant of various functional groups and a broad range of substrates.The mechanism experiments suggested an involvement of 5-exo-trig cyclization and a radical pro-cess in this transformation.
TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.
