No abstract

A 3.1% Ru/UiO-66 material was prepared by adsorption of RuCl 3 from ethyl acetate on to MOF UiO-66, followed by reduction with NaBH 4 . The presence of acid–base and ox-red sites allows this 3.1% Ru/UiO-66 material acting as a bifunctional catalyst for the reduction of nitroarenes and tandem reaction of alcohol oxidation/Knoevenagel condensation. The high efficiency of 3.1% Ru/UiO-66 was demonstrated in the reduction of nitroarenes to amines. This system can be applied as a catalyst for at least six successive cycles without loss of activity. The 3.1% Ru/UiO-66 catalyst also was active in the tandem aerobic oxidation of alcohols/Knoevenagel condensation with malononitrile. However, the activity of this catalyst strongly decreased in the second cycle. A combination of physicochemical and catalytic experimental data indicated that Ru nanoparticles are the active sites both for the catalytic reduction of nitro compounds and the aerobic oxidation of alcohols. The activity for the Knoevenagel condensation reaction was from the existence of the “Zr n + –O 2– Lewis acid–base” pair in the framework of UiO-66.

No abstract

No abstract

Disclosed herein is a direct C−H trifluoromethylation of quinoxalin‐2(1H)‐ones with sodium trifluoromethanesulfinate. This protocol affords a series of 3‐trifluoromethylquinoxalin‐2(1H)‐one derivatives in moderate to excellent yields under transition‐metal‐free conditions. The present methodology features utilization of the inexpensive trifluoromethyl source without transition‐metal‐catalysts, mild reaction conditions and high functional group tolerance, which promises a convenient and efficient access to pharmaceutically interesting quinoxalinones.magnified image

A new alumina-supported cobalt-nickel oxide catalyst for the synthesis of acetonitrile from ethanol and ammonia was prepared by coprecipitation-kneading method. The parameters influencing the reaction were studied thoroughly and an optimized process, which is running the reaction at 380°C under atmospheric pressure while keeping the ammonia/alcohol molar ratio of 5 and GHSV of 1,163 h -1 , was obtained. Under the optimized conditions the catalyst reached its best performance when being on stream for 40 h, at which the yield of acetonitrile was 92.6%. Then the selectivity to acetonitrile decreased gradually but the yield of acetonitrile always remained higher than 81% within 720 h. The samples of the fresh and used catalyst were characterized by XRD, XPS, TEM, EDX and N 2 adsorption-desorption analysis. The results revealed that carbon deposition and formation of metal carbides from the active species in the catalytic runs led to the deterioration of the catalyst.

A copper-catalyzed direct CÀ H difluoroacetylation of quinoxalinones at the C-3 position with ethyl bromodifluoroacetate has been developed. In this reaction, diverse difluoroacetylated quinoxalin-2(1H)-ones with a wide range of functional groups could be obtained in moderate to good yields, using cheap, commercially available reagents. This protocol would offer a meaningfully synthetic method for pharmacologically interesting difluoroacetylated quinoxalin-2(1H)-one derivatives.

A facile and effective alkoxylation protocol of quinoxalin-2(1H)-ones with primary or secondary alcohols via cross-dehydrogenative coupling under catalyst-free conditions has been disclosed. This method provides a powerful and convenient access to 3-alkoxylquinoxalin-2(1H)-ones in good to excellent yields by utilizing PhI(OTFA) 2 as an oxidant and allows to easily obtain potential drug molecules containing 3-alkoxylquinoxalin-2(1H)-one skeletons.