排序方式: 共有33条查询结果,搜索用时 15 毫秒
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Francisco Palacios Author Vitae Concepción Alonso Author VitaeAuthor Vitae Gloria Rubiales Author VitaeAuthor Vitae 《Tetrahedron》2007,63(3):523-575
Recent advances in the aza-Wittig reaction of phosphazene derivatives with several carbonyl compounds are reviewed. Phosphazenes afford inter- and intramolecular aza-Wittig reactions with different compounds such as aldehydes, ketones, esters, thioesters, amides, anhydrides and sulfimides. One of the most important applications of this reaction is the synthesis of a wide range of acyclic and heterocyclic compounds, ranging from simple monocyclic compounds to complex polycyclic and macrocyclic systems. 相似文献
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Flow analysis techniques for phosphorus: an overview 总被引:2,自引:0,他引:2
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径向磁化的多环嵌套永磁轴承轴向磁力解析模型 总被引:1,自引:0,他引:1
为了解决径向磁化双环永磁轴承轴向磁力偏小的问题,设计了径向磁化多环嵌套永磁轴承新结构。基于磁路及虚功原理法,结合径向磁化多环嵌套永磁轴承结构特点及线性叠加原理,建立了径向磁化多环嵌套永磁轴承轴向磁力解析模型。模型表明:径向磁化多环嵌套永磁轴承轴向磁力与磁环剩磁平方成正比,磁力随磁环间隙的增大而减小,随磁环数的增大而增大;在正常轴向工作范围内,轴向磁力随轴承轴向偏移的增大而增大。模型计算结果与有限元计算结果基本吻合。对比计算说明:径向磁化多环嵌套永磁轴承轴向磁力远大于由原多嵌套磁环所构成的若干双环永磁轴承轴向磁力之和。 相似文献
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Sulfated tungstate was found to be an effective heterogeneous and reusable catalyst for hydroxy group activation–mediated preparation of benzylic ethers including p-methoxybenzylic ethers of a wide range of alcohols and phenols under mild reaction conditions. 相似文献
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Hélène PellissierAuthor Vitae 《Tetrahedron》2011,67(21):3769-3802
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《Tetrahedron letters》2017,58(36):3493-3495
A novel and efficient synthetic approach to enantiopure 3-substituted pyrrolidine skeleton from readily available (S)-PMB glycidyl ether as a starting material and its application to the asymmetric synthesis of pyrrolidine core 1 of serotonin norepinephrine reuptake inhibitors (SNRIs) 2 and 3 are described. The synthesis utilizes the organocatalyzed asymmetric Michael addition reaction as key step. 相似文献
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Kazuhiro WatanabeTadashi Katoh 《Tetrahedron letters》2011,52(41):5395-5397
In this Letter, a selective deprotection of the alcohol protecting 3,4-dimethoxybenzyl (3,4DMB) group is described. The hypervalent iodine(III) reagent phenyliodine bis(trifluoroacetate) (PIFA) is found to be an efficient reagent for the chemoselective deprotection of 3,4DMB ethers in the presence of benzyl, p-methoxybenzyl, methoxymethyl, tert-butyldimethylsilyl, and tert-butyldiphenylsilyl ethers under mild conditions. This is the first example of the selective deprotection of the 3,4DMB group from a hydroxy group with PIFA. 相似文献