Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The tra...Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.展开更多
Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had hi...Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors, chlorsulfuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.展开更多
基金financial support from the Marine S&T Fund of Shandong Province for Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the National Key Research&Development Program of China(No.2022YFA2104902)the National Natural Science Foundation of China(Nos.21977088 and22377114)。
文摘Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.
文摘Study on relative sensitivity of maize (Zea mays L.) Nongda108 and Nongda3138 to sulfony-lurea herbicide chlorsulfuron and tribenuron-methyl using maize taproot length by sand bioassy indicated that, Nongda3138 had higher tolerance to chlorsulfuron and tribenuron-methyl than Nongda108 did. Chlorsulfuron had stronger growth inhibition to maize Nongda108 and Nongda3138 than tribenuron-methyl did. Study on target enzyme of sulfonylurea herbicide acetolactate synthase (ALS) showed that, chlorsulfuron and tribenuron-methyl inhibited ALS in vitro strongly, and non-competitively. In the same concentration of inhibitors, chlorsulfuron had stronger ALS activity inhibition than tribenuron-methyl did. Lower level of chlorsulfuron and tribenuron-methyl has no ALS activity inhibition in vivo, the ALS inhibition only occurred in the condition of high concentration of chlorsulfuron and tribenuron-methyl in vivo.
