As important natural and pharmaceutical motifs,the catalytic construction of structurally diverse 3,3-disubstituted oxindoles often requires elaborate synthetic efforts on optimizations.Herein,we developed a simple an...As important natural and pharmaceutical motifs,the catalytic construction of structurally diverse 3,3-disubstituted oxindoles often requires elaborate synthetic efforts on optimizations.Herein,we developed a simple and divergent approach for constructing reverse-prenylated and prenylated oxindoles launched by Ni catalysis with bulk chemical isoprene.Using C3-unsubstituted oxindoles as starting materials,mono reverse-prenylation was demonstrated in high chemo-and regioselectivities facilitated by the combination of Ni(0)and monodentate phosphine ligand.Using the obtained reverse-prenylated oxindoles as versatile synthon,substitutions at the pseudobenzylic position with various electrophiles created vicinal quaternary centers in a concise way.With the help of additives(PPh3 and NaH),air could be directly used as green oxidant to construct prenylated and reverse-prenylatedα-hydroxy-oxindoles divergently from the same substrates.In situ esterification of prenylatedα-hydroxy-oxindoles allowed subsequent Friedel-Crafts substitutions with diverse nucleophiles to deliver prenyl substituted dimeric or spiro-oxindoles.This protocol provides a divergent synthetic approach for the construction of highly functionalized 3,3-disubstituted oxindoles,which have been otherwise difficult to access in a unified approach.展开更多
Metabolizing enzymes play important roles in the detoxification of various pollutants in aquatic organisms, thereby they can also be used to provide early-warning signals of environmental risks. Real-time quantitative...Metabolizing enzymes play important roles in the detoxification of various pollutants in aquatic organisms, thereby they can also be used to provide early-warning signals of environmental risks. Real-time quantitative reverse-transcription polymerase chain reaction assays were developed to quantify cytochrome P450 1A （CYP1A）, superoxide dismutase （SOD）, glutathione peroxidase （GPx）, catalase （CAT）, and glutathione-S-transferase （GST） in crucian carp （Carassius auratus）. The methods were then used to detect the respective mRNA expression levels in liver tissue in wild crucian carp from the Hun River, North China. CYP1A mRNA expression was significantly up-regulated in fish from stations $5, $6, and $8 （p 〈 0.05）. SOD mRNA expression was significantly down-regulated in downstream areas relative to fish from upstream sites （p 〈 0.05）; GPx and CAT mRNA expression levels were also down-regulated at $9 （p 〈 0.05）. In contrast, GST mRNA expression showed no obvious change between fish collected from up- or downstream areas of the river. Finally, an integrated biomarker response was used to evaluate the integrated impact of pollutants in the Hun River and allow better comprehension of the real toxicological risk of these investigated sites.展开更多
目的研究逆转录酶抑制剂(AZT)对卵巢癌细胞 HO-8910端粒酶活性及生长的影响。方法采用 TRAP-ELISA 方法检测卵巢癌 HO-8910细胞在 AZT 作用前后端粒酶活性的变化,用 MTT 分析法对不同浓度 AZT 作用的卵巢癌 HO-8910细胞进行药物敏感实验...目的研究逆转录酶抑制剂(AZT)对卵巢癌细胞 HO-8910端粒酶活性及生长的影响。方法采用 TRAP-ELISA 方法检测卵巢癌 HO-8910细胞在 AZT 作用前后端粒酶活性的变化,用 MTT 分析法对不同浓度 AZT 作用的卵巢癌 HO-8910细胞进行药物敏感实验,透射电镜观察其细胞超微结构的变化,流式细胞仪测定凋亡细胞含量。结果 AZT 作用后的 HO-8910细胞端粒酶活性明显受抑制,且对细胞的生长有抑制作用,并有时间依赖关系和剂量依赖关系。形态学超微结构显示细胞器扩张和肿胀,核染色质边集。流式细胞仪检测凋亡峰含量为14.2%。结论 AZT 能明显抑制卵巢癌细胞的端粒酶活性及卵巢癌细胞的增殖,因而为卵巢癌和其它肿瘤的治疗尝试一种新的有效的方法。展开更多
文摘As important natural and pharmaceutical motifs,the catalytic construction of structurally diverse 3,3-disubstituted oxindoles often requires elaborate synthetic efforts on optimizations.Herein,we developed a simple and divergent approach for constructing reverse-prenylated and prenylated oxindoles launched by Ni catalysis with bulk chemical isoprene.Using C3-unsubstituted oxindoles as starting materials,mono reverse-prenylation was demonstrated in high chemo-and regioselectivities facilitated by the combination of Ni(0)and monodentate phosphine ligand.Using the obtained reverse-prenylated oxindoles as versatile synthon,substitutions at the pseudobenzylic position with various electrophiles created vicinal quaternary centers in a concise way.With the help of additives(PPh3 and NaH),air could be directly used as green oxidant to construct prenylated and reverse-prenylatedα-hydroxy-oxindoles divergently from the same substrates.In situ esterification of prenylatedα-hydroxy-oxindoles allowed subsequent Friedel-Crafts substitutions with diverse nucleophiles to deliver prenyl substituted dimeric or spiro-oxindoles.This protocol provides a divergent synthetic approach for the construction of highly functionalized 3,3-disubstituted oxindoles,which have been otherwise difficult to access in a unified approach.
基金supported by the Water Pollution Control and Management(No.2009ZX07528)
文摘Metabolizing enzymes play important roles in the detoxification of various pollutants in aquatic organisms, thereby they can also be used to provide early-warning signals of environmental risks. Real-time quantitative reverse-transcription polymerase chain reaction assays were developed to quantify cytochrome P450 1A （CYP1A）, superoxide dismutase （SOD）, glutathione peroxidase （GPx）, catalase （CAT）, and glutathione-S-transferase （GST） in crucian carp （Carassius auratus）. The methods were then used to detect the respective mRNA expression levels in liver tissue in wild crucian carp from the Hun River, North China. CYP1A mRNA expression was significantly up-regulated in fish from stations $5, $6, and $8 （p 〈 0.05）. SOD mRNA expression was significantly down-regulated in downstream areas relative to fish from upstream sites （p 〈 0.05）; GPx and CAT mRNA expression levels were also down-regulated at $9 （p 〈 0.05）. In contrast, GST mRNA expression showed no obvious change between fish collected from up- or downstream areas of the river. Finally, an integrated biomarker response was used to evaluate the integrated impact of pollutants in the Hun River and allow better comprehension of the real toxicological risk of these investigated sites.
文摘目的研究逆转录酶抑制剂(AZT)对卵巢癌细胞 HO-8910端粒酶活性及生长的影响。方法采用 TRAP-ELISA 方法检测卵巢癌 HO-8910细胞在 AZT 作用前后端粒酶活性的变化,用 MTT 分析法对不同浓度 AZT 作用的卵巢癌 HO-8910细胞进行药物敏感实验,透射电镜观察其细胞超微结构的变化,流式细胞仪测定凋亡细胞含量。结果 AZT 作用后的 HO-8910细胞端粒酶活性明显受抑制,且对细胞的生长有抑制作用,并有时间依赖关系和剂量依赖关系。形态学超微结构显示细胞器扩张和肿胀,核染色质边集。流式细胞仪检测凋亡峰含量为14.2%。结论 AZT 能明显抑制卵巢癌细胞的端粒酶活性及卵巢癌细胞的增殖,因而为卵巢癌和其它肿瘤的治疗尝试一种新的有效的方法。
