查询词典 ketenes
- 与 ketenes 相关的网络例句 [注:此内容来源于网络,仅供参考]
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Ketenes, notably dimethyl ketene, readily undergo oligomerization and polymerization
烯酮,特别是二甲基烯酮,很容易齐聚和聚合。
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Because of their strong nucleophility of NHCs, the asymmetric Staudinger reaction between ketenes and imines catalyzed by chiral NHC was achieved, gave -lactams with excellent enantioselectivities.
中文摘要我们组利用氮杂环卡宾的亲核性,成功地实现了氮杂环卡宾催化的烯酮与亚胺的Staudinger反应。
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In the second part of this thesis, a formal [2+2] cycloaddition ketenes and dialkyl azodicarboxylates was studied. We found that by adjusting the substituents in the diazenes, the reaction mode can be completely switched, and furnish four-membered-ring products, aza-b-lactams, the enantioselectivity was up to 91%.
经研究发现,通过对偶氮化合物取代基团的改变,我们可以实现[4+2]环加成反应到[2+2]环加成反应的转变,在手性氮杂环卡宾的作用下,对具有各种取代基的烯酮都可以很好的产率得到氮杂b-内酰胺,其对映选择性最高可以达到91%。
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As open-chain hydroxy aldehydes and hydroxyl ketenes, the monosaccharides are very reactive.
以开链的羟基醛和羟基酮形式存在的单糖非常活泼。
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In the first part of this thesis, a formal [4+2] cycloaddition of ketenes with N-benzoyldiazenes catalyzed by chiral NHCs was studied, which gave 1,3,4-oxadiazin-6-ones in very high yields and enantioselectivites.
论文的第一部分内容是在手性氮杂环卡宾的催化下,烯酮与N-苯甲酰偶氮化合物的环加成反应,合成各种手性的噁二嗪酮,它们还可以经过简单的两步一锅法制备手性氨基酯。
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According to the results of the examination, the stronger the electron-withdrawing protective group of imines, the better the cis-selectivity of the reaction, 68% yield, trans:cis is 99:1 diastereoselectivity could be leaded by Ts-imines (4-methyl-N-methylene-benzenesulfonaides) with a substituent [2,4-(CH3O)2C6H3], Substrate scope investigation revealed that a wide variety of ketenes and imines could react smoothly to afford corresponding,β-lactams.
实验结果表明,亚胺的保护基团吸电子能力越强,越有利于顺式产物的生成。对甲苯磺酰基保护的取代基为2,4-二甲氧苯基的亚胺参与的该反应可得到68%的产率,反式:顺式=99:1的非对映选择性。底物拓展过程中发现Staudinger反应适用于多种不同的亚胺与烯酮。
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Its reaction with ketenes generated in situ from acid chlorides afforded-4--azetidin-2-one, thus provided a 14-member library of-4--azetidin-2-one with yields 76~91% and an excellent stereoselectivity.
我们从PEG支载的苯甲醛出发,经腙的制备及其氯代之后,在三辛胺作用下,由氯代腙原位生成的腈亚胺与亚胺发生[3+2]偶极环加成反应,得到PEG支载四芳基-4,5-二氢-1,2,4-三氮唑衍生物。
- 推荐网络例句
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The split between the two groups can hardly be papered over.
这两个团体间的分歧难以掩饰。
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This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.
这种做法不仅鼓励了更多的反应,而且减少跟风的可能性。
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The new PS20 solar power tower collected sunlight through mirrors known as "heliostats" to produce steam that is converted into electricity by a turbine in Sanlucar la Mayor, Spain, Wednesday.
聚光:照片上是建在西班牙桑路卡拉马尤城的一座新型PS20塔式太阳能电站。被称为&日光反射装置&的镜子将太阳光反射到主塔,然后用聚集的热量产生蒸汽进而通过涡轮机转化为电力