排序方式: 共有46条查询结果,搜索用时 22 毫秒
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Fernanda M.F. Roleira Fernanda Borges José A. Paixão Rui A. Carvalho 《Journal of fluorine chemistry》2009,130(2):169-2299
In this work we describe and compare the synthesis of four new hexylamides of hydrocinnamic acids, namely hexylamide of hydrocinnamic, 3,4-dimethoxyhydrocinnamic, 4-hydroxy-3-methoxyhydrocinnamic and 3,4-dihydroxyhydrocinnamic acids via pentafluorophenyl esters (PFPEs) versus pentafluorophenyl thioesters (PFPTs) intermediates. It was found that the PFPE are the best intermediates for this kind of synthesis giving reactions with less by products, easier work-up, higher overall yields and with the best reactivity towards hexylamine. The X-ray structures of two PFPE are also reported. 相似文献
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Yusuke Tsuda Dr. Akira Shigenaga Kohei Tsuji Masaya Denda Kohei Sato Keisuke Kitakaze Takahiro Nakamura Dr. Tsubasa Inokuma Prof. Kohji Itoh Prof. Akira Otaka 《ChemistryOpen》2015,4(4):448-452
Peptide thioesters are very useful in protein chemistry, and chemistry- and biochemistry-based protocols are used for the preparation of thioesters. Among such protocols, only a few biochemistry-based approaches have been use for naturally occurring peptide sequences. The development of chemistry-based protocols applicable to natural sequences remains a challenge, and the development of such methods would be a major contribution to protein science. Here, we describe the preparation of peptide thioesters using innovative methodology that features nickel(II)-mediated alcoholysis of a naturally occurring peptide sequence, followed by O−N and N−S acyl transfers. This protocol involves sequential quadruple acyl transfer, termed SQAT. Notably, the SQAT system consists of sequential chemical reactions that allow naturally occurring peptide sequences to be converted to thioesters without requiring an artificial chemical unit. 相似文献
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Senthil NarayanaperumalEduardo E. Alberto Kashif GulCristiane Yuriko Kawasoko Luciano DornellesOscar E.D. Rodrigues Antonio Luiz Braga 《Tetrahedron》2011,67(25):4723-4730
A straightforward and efficient methodology is described to synthesize structurally diverse diorganyl selenides, sulfides, seleno- and thioesters by using commercially available Zn dust in ionic liquid. Excellent yields were achieved under neutral conditions at room temperature in a short time. The solvent/ionic liquid is reusable and exhibited higher performance as compared with organic solvents. 相似文献
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3-Phenyl propylthiol esters were investigated as “activatable” solution phase linkers. These linkers can be activated with silver salts and upon treatment with amines can be converted to the corresponding amides. Under unactivated conditions, the linker is stable to a variety of reagents and reaction conditions including treatment with amines. 相似文献
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Hiroto Kudo Shinya Makino Tadatomi Nishikubo 《Journal of polymer science. Part A, Polymer chemistry》2007,45(4):680-687
The ring‐crossover polymerization of cyclic dithioester 1 was performed in the presence of quaternary onium salts as catalysts at 70–150 °C for 24 h in NMP. It was found that predictable cyclic polymers with the same repeating structures as 1 were obtained with Mns in the range between 700 and 3,500, quantitatively. It was observed that intermolecular and intramolecular thioester‐exchange reactions proceeded between cyclic monomer 1 and resulting cyclic polymers under thermodynamic control to give a lower‐molecular‐weight cyclic polymer with a lower polydispersity ratio (Mn = 2,400, Mw/Mn = 1.70). © 2006Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 680–687, 2007 相似文献
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Interconvertible Living Radical and Cationic Polymerization through Reversible Activation of Dormant Species with Dual Activity 下载免费PDF全文
Dr. Hiroshi Aoshima Mineto Uchiyama Prof. Dr. Kotaro Satoh Prof. Dr. Masami Kamigaito 《Angewandte Chemie (International ed. in English)》2014,53(41):10932-10936
The polymerization of vinyl monomers generally requires the selection of an appropriate single intermediate, whereas in copolymerization, the selection of the comonomer is limited by the intermediate. Herein, we propose interconvertible dual active species that can connect comonomers through different mechanisms to produce specific comonomer sequences in a single polymer chain. More specifically, two different stimuli, that is, a radical initiator and a Lewis acid, are used to activate the common dormant C? SC(S)Z group into radical and cationic species, thereby inducing interconvertible radical and cationic copolymerization of acrylate and vinyl ether to produce a copolymer chain that consists of radically and cationically polymerized segments. The dual reversible activation provides control over molecular weights and multiblock copolymers with tunable segment lengths. 相似文献
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Inside Cover: Interconvertible Living Radical and Cationic Polymerization through Reversible Activation of Dormant Species with Dual Activity (Angew. Chem. Int. Ed. 41/2014) 下载免费PDF全文
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Yao He Da‐Liang Qu Min Yu Prof. Zhang‐Yong Hong Prof. Dr. Lei Liu 《Angewandte Chemie (International ed. in English)》2015,54(7):2194-2198
Fully unprotected peptide o‐aminoanilides can be efficiently activated by NaNO2 in aqueous solution to furnish peptide thioesters for use in native chemical ligation. This finding enables the convergent synthesis of proteins from readily synthesizable peptide o‐aminoanilides as a new type of crypto‐thioesters. The practicality of this approach is shown by the synthesis of histone H2B from five peptide segments. Purification or solubilization tags, which are sometimes needed to improve the efficiency of protein chemical synthesis, can be incorporated into the o‐aminoanilide moiety, as demonstrated in the preparation of the cyclic protein lactocyclicin Q. 相似文献