共查询到19条相似文献,搜索用时 62 毫秒
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聚合物固载化聚乙二醇季铵盐型相转移催化剂在有机合成中的应用 总被引:1,自引:0,他引:1
本文考察了固载化聚乙二醇季铵盐作为相转移催化剂在咪唑N-烷基化反应,Williamson混合醚的合成以及卤素转换反应中的应用,着重研究了改变反应条件对催化反应的影响,就催化剂的重复使用能力和催化剂结构对其催化效率的影响也略作探讨。实验证明,本催化剂有较高的催化活性,有实际应用价值。 相似文献
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聚合物支载的不对称有机合成 总被引:3,自引:0,他引:3
聚合物支载的不对称有机合成比相应的小分子合成体系有独特的优越性。本文综述了近10年来取得了较大进展的聚合物支载的不对称有机合成体系。 相似文献
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本文重点介绍了目前实验室和市场上可用于固相组合合成的含羟基的聚合物载体及其主要的化学反应性能。 相似文献
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Carbohydrates contain numerous hydroxyl groups and sometimes amine functionalities which lead to a variety of complex structures. In order to discriminate each hydroxyl group for the synthesis of complex oligosaccharides, protecting group manipulations are essential. Although the primary role of a protecting group is to temporarily mask a particular hydroxyl/amino group, it plays a greater role in tuning the reactivity of coupling partners as well as regioselectivity and stereoselectivity of glycosylations. Several protecting groups offer anchimeric assistance in glycosylation. They also alter the solubility of substrates and thereby influence the reaction outcome. Since oligosaccharides comprise branched structures, the glycosyl donors and acceptors need to be protected with orthogonal protected groups that can be selectively removed one at a time without affecting other groups. This minireview is therefore intended to provide a discussion on new protecting groups for amino and hydroxyl groups, which have been introduced over last ten years in the field of carbohydrate synthesis. These protecting groups are also useful for synthesizing non‐carbohydrate target molecules as well. 相似文献
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Sascha Knauer Niklas Koch Christina Uth Reinhard Meusinger Olga Avrutina Harald Kolmar 《Angewandte Chemie (International ed. in English)》2020,59(31):12984-12990
The growing interest in synthetic peptides has prompted the development of viable methods for their sustainable production. Currently, large amounts of toxic solvents are required for peptide assembly from protected building blocks, and switching to water as a reaction medium remains a major hurdle in peptide chemistry. We report an aqueous solid‐phase peptide synthesis strategy that is based on a water‐compatible 2,7‐disulfo‐9‐fluorenylmethoxycarbonyl (Smoc) protecting group. This approach enables peptide assembly under aqueous conditions, real‐time monitoring of building block coupling, and efficient postsynthetic purification. The procedure for the synthesis of all natural and several non‐natural Smoc‐protected amino acids is described, as well as the assembly of 22 peptide sequences and the fundamental issues of SPPS, including the protecting group strategy, coupling and cleavage efficiency, stability under aqueous conditions, and crucial side reactions. 相似文献
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Michael Schelhaas Herbert Waldmann 《Angewandte Chemie (International ed. in English)》1996,35(18):2056-2083
The choice of protecting groups is one of the decisive factors in the successful realization of a complex, demanding synthetic project. The protecting groups used influence the length and efficiency of the synthesis and are often responsible for its success or failure. A wide range of blocking groups are currently available for the different functional groups; however, an overall strategy combining these different masking techniques in an advantageous and reliable manner has never been proposed or at best only for individual cases. This review attempts to make a contribution to filling this gap. First a very short overview of the most commonly used protecting groups will be given, in which they are classified according to their lability and not according to the functional group they protect. This classification clarifies coherent concepts for the development of blocking strategies. On the basis of this brief summary reliable strategies will then be illustrated and developed with selected examples from the recent literature by which protecting groups may be combined successfully and advantageously in synthetic projects of differing degrees of complexity and difficulty. 相似文献
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Mesram Manoj Kumar Dr. Parikibanda Venkataramana Prof. Parikibanda Yadagiri Swamy Dr. Yadaiah Chityala 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(70):17713-17721
A new route to synthesis of various mono-N-substituted hydrazines and hydrazides by involving in a new C−N bond formation by using N-amino-1,8-naphthalimide as a regenerated precursor was invented. Aniline and phenylhydrazines are reproduced upon reacting these individually with 1,8-naphthalic anhydride followed by hydrazinolysis. The practicality and simplicity of this C−N dihalo alkanes; developed a synthon for bond formation protocol was exemplified to various hydrazines and hydrazides. N-amino-1,8-naphthalimide is suitable synthon for transformation for selective formation of mono-substituted hydrazine and hydrazide derivatives. Those are selective mono - amidation of hydrazine with acid halides; mono-N-substituted hydrazones from aldehydes; synthesis of N-aminoazacycloalkanes from acetohydrazide scaffold and inserted to hydroxy derivatives; distinct synthesis of N,N-dibenzylhydrazines and N-benzylhydrazines from benzyl halides; synthesis of N-amino-amino acids from α-halo esters. Ecofriendly reagent N-amino-1,8-naphthalimide was regenerated with good yields by the hydrazinolysis in all procedures. 相似文献
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Benzyloxycarbonyl-glutamylpeptide p-nitrophenylesters were prepared from protected amino acids, e.g.: p-nitrophenyl-glutamate as carboxyl component and aminoacid or peptide p-nitrophenylesters as amino components by different kinds of peptide coupling methods. Mixed carbonic anhydride and azide methods gave good results. The p-nitrophenylesters existed as temporary protecting groups, so the peptide couplings proceeded together with simultaneous activation. The conditions and applications of the procedure are discussed. The peptides having one or more active ester groups were used to form amides by their aminolysis with derivatives of ethylamine or were polycondensated (after deprotection) to obtain polypeptides. 相似文献
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Hongpeng Yang Prof. Tao Peng Prof. Xiaoxue Wen Tingting Chen Prof. Yunbo Sun Prof. Shuchen Liu Gang Wang Prof. Shouguo Zhang Prof. Lin Wang 《ChemistryOpen》2021,10(4):497-502
A new kind of photolabile protecting group (PLPG) for carboxyl moieties was designed and synthesized as the linker between resin and peptide. This group can be used for the protection of amino acid carboxyl groups. The peptide was synthesized on Nph (2-hydroxy-3-(2-nitrophenyl)-heptanoic acid)-derivatized resins and could be cleaved under UV exposure, thus avoiding the necessity for harsh acid-mediated resin cleavage. The PLPG has been successfully used for solid-phase synthesis of peptides. 相似文献