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1.
Yi Jiang Yijun Zhang Boon Chong Lee Prof. Dr. Ming Joo Koh 《Angewandte Chemie (International ed. in English)》2023,62(38):e202305138
Glycosyl radical functionalization is one of the central topics in synthetic carbohydrate chemistry. Recent advances in metal-catalyzed cross-coupling chemistry and metallaphotoredox catalysis provided powerful platforms for glycosyl radical diversification. In particular, the discovery of new glycosyl radical precursors in conjunction with these advanced reaction technologies have significantly expanded the space for glycosyl compound synthesis. In this Review, we highlight the most recent progress in this area starting from 2021, and the reports included will be categorized based on different reaction types for better clarity. 相似文献
2.
Ferenc Sajtos 《Tetrahedron letters》2005,46(31):5191-5194
Phenyl and trityl 2-O-sulfonyl-1-thio-α-d-manno- and β-d-glucopyranosides were reacted with sodium azide to yield 2-S-phenyl or 2-S-trityl-d-gluco- and d-mannopyranosyl azides, respectively. Usually, both anomers were formed in approximately equal amounts and formation of glycals was also observed in some cases. The product distribution of these reactions depends on the nature of the aglycone, the applied reagent and also on the solvent. These results can be rationalised by the intermediacy of episulfonium as well as oxocarbenium ions. Oxidation of the 2-S-trityl-α-d-glucopyranosyl or α-d-mannopyranosyl azides by Oxone®, gave sodium 2-sulfonato-α-d-gluco- and α-d-mannopyranosyl azides, respectively. 相似文献
3.
《中国化学会会志》2018,65(4):430-434
An efficient pseudo‐three‐component synthesis of tetraketones is described by one‐pot condensation of 5,5‐dimethylcyclohexane‐1,3‐dione and aldehydes using ZnS nanoparticles at room temperature. This method provides several advantages such as mild reaction conditions, applicability to a wide range of substrates, reusability of the catalyst, and low catalyst loading. 相似文献
4.
Tandem cascade reactions of allylazides and olefinic dipolarophiles to give cis‐fused 2,3,7‐triazabicyclo [3.3.0]octenes ( 5, 6 or 7 ) are reported. Therein, an intermolecular dipolar cycloaddition of azide and alkene gave a triazoline which was followed by isomerization of the triazoline to a diazoester ( 4 ) and then an intramolecular dipolar cycloaddition from the diazo functional group and the double bond in 4 to give 5 . Compound 5 may further more undergo a Michael addition to give 7‐substituted‐ 2,3,7‐ triazabicyclo [3.3.0]oct‐2‐ene ( 6 ) or a tautomerization to give 2,3,7‐triazabicyclo[3.3.0]oct‐3‐ene ( 7 ). The reaction may be manipulated to stop at a particular stage by adopting a suit able solvent or an appropriate temperature. 相似文献
5.
A series of isoquinolinones have been synthesized by one‐pot Curtius rearrangement and cyclization of the corresponding cinnamoyl azides using Hg(OAc)2 as the catalyst under refluxing o‐dichlorobenzene. This is the first time that the intermediate carbamoylisoquinolinone 4 in the synthesis of isoquinolinones has been reported. The nature of the substituent on the aromatic ring was found to be crucial to obtaining high yields of isoquinolinone. The mechanism of the reaction was also discussed. 相似文献
6.
Ling Hua CAO * Hong Yun GAO Chuan Jian ZHOU Yu Ting LIU College of Chemistry Chemical Engineering Xinjiang University Urumqi State Key Laboratory of Elements-Organic Chemistry Nankai University Tianjin 《中国化学快报》2004,(2)
Sugar derivatives whose molecules contain trivalent phosphorus groups have been coming into use for different scientific purposes, including the synthesis of metal com- plexes. These metal complexes of glycosyl phosphites are effective chiral catalysts in enantioselective synthesis1-5such as hydrogenation, cyclopropylation, hydro phosphina- tion and hydrosilylation of achiral olefin. Furthermore, this kind of compounds are also widely applied in biology and medicine area and open up a new fie… 相似文献
7.
Shiyang Xu Wei Zhang Caiyi Li Yanjing Li Hongxin Zeng Prof. Yingwei Wang Yang Zhang Prof. Dawen Niu 《Angewandte Chemie (International ed. in English)》2023,62(16):e202218303
We herein report a method that enables the generation of glycosyl radicals under highly acidic conditions. Key to the success is the design and use of glycosyl sulfinates as radical precursors, which are bench-stable solids and can be readily prepared from commercial starting materials. This development allows the installation of glycosyl units onto pyridine rings directly by the Minisci reaction. We further demonstrate the utility of this method in the late-stage modification of complex drug molecules, including the anticancer agent camptothecin. Experimental studies provide insight into the reaction mechanism. 相似文献
8.
A convenient and environmentally friendly reactor for the synthesis of glycosyl bromides via ultrasound irradiation was designed. Peracetylated glycosyl bromides were synthesized from free saccharides by means of a one-pot method. Benzoylated and 6-subsituted glycosyl bromides were prepared from protected saccharides. The glycosyl bromides were obtained in isolated yields of 83% to 96%. 相似文献
9.
Methanesulfonic acid efficiently catalyzes the one‐pot, three component reaction of an aromatic aldehyde, malonitrile and α or β‐naphthol to yield 2‐amino‐4H‐chromenes in very good yields. 相似文献
10.
An efficient procedure for the preparation of aryl azides using sonication is described. The convenient sonication-mediated azidation protocol is applicable to aryl compounds under mild conditions with aqueous solution of sodium dichloroiodate and sodium azide. Aryl azides were obtained in excellent yields from a variety of aryl compounds in short reaction times without affecting sensitive functional groups. 相似文献
11.
László Kalmár Károly Ágoston Zoltán Szurmai Boglárka Döncző János Kerékgyártó 《Journal of carbohydrate chemistry》2013,32(3):203-219
The fully O-benzylated pentasaccharide glycosyl azide representing the common core structure of N-glycans was synthesized. The β-mannosidic linkage was created by C-2 epimerization of the initially introduced β-d- gluco-unit via DMSO/Ac2O oxidation followed by stereoselective reduction with tetrabutylammonium borohydride. 相似文献
12.
A Mild and Simple One‐pot Synthesis of 2‐Substituted Benzimidazole Derivatives Using DDQ as an Efficient Oxidant at Room Temperature 下载免费PDF全文
A series of 2‐substituted benzimidazoles were prepared through one‐pot reaction of o‐phenylenediamine with various aryl aldehydes in the presence of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) in acetonitrile as solvent at room temperature. The reactions were smoothly preceded in excellent yields and short reaction times with an easy work‐up. The pure benzimidazoles as products were confirmed and characterized by physical and spectral data. 相似文献
13.
Novel One‐Pot Three‐Component Reaction for the Synthesis of Functionalized Spiroquinazolinones 下载免费PDF全文
Mahdieh Tajbakhsh Sorour Ramezanpour Saeed Balalaie Hamid Reza Bijanzadeh 《Journal of heterocyclic chemistry》2015,52(5):1559-1564
A wide variety of spiroquinazolinone derivatives have been synthesized via a one‐pot three‐component reaction of isatoic anhydride, cyclic ketones, and hydrazides in the presence of catalytic amount (20 mol%) of H3PO3 in ethanol. Mild reaction conditions, high atom economy, operational simplicity, and good to high yields are the key advantages of the present protocol. 相似文献
14.
在微波促进下, 利用酮糖(1)及糖酸内酯(4)与叶立德(2, Ph3PCHCOOEt)的Wittig反应, 立体选择性地合成了糖基烯丙酸酯类化合物(3和5), 反应效率显著提高, 反应时间由原来的20 h缩短为10 min; 并且研究了不同反应溶剂对反应立体选择性的影响. 提供了一种高效、 简便合成含有烯丙酸酯类高碳糖衍生物的方法. 相似文献
15.
16.
The one‐pot synthesis of water‐soluble and biologically compatible yellow CdSe quantum dots (QDs) featuring the use of glutathione (GSH) as the capping and reducing agent was achieved under aqueous conditions at 150 °C. The synthesized yellow CdSe QDs with quantum yield (QY) up to 20% exhibit zinc blende cubic structure particles with an average diameter of 4‐5 nm. It was found that both molar ratio of Se/Cd and reaction time had a significant effect on size distribution of GSH‐CdSe QDs. Meanwhile, the interaction of QDs bioconjugated to bovine hemoglobin (BHb) was studied by absorption and fluorescence(FL) spectra. With addition of BHb, the FL intensity of CdSe QDs largely quenched due to the static mechanism. The linear range is 5.0 × 10?8 mol/L to 3.0 × 10?6 mol/L, and the correlation coefficient is 0.9991, suggesting that could be used as a probe to label biological molecules and bacterial cells. 相似文献
17.
Shasha Fu Qizhuang Sun Dingyun Li Meiting Dong Shuxian Liu Chaobiao Huang 《中国化学会会志》2013,60(3):309-313
Described herein is a novel one‐pot aqueous synthesis of ZnSe nanocrystals has featuring the utilization of Na2SeO3 and Zn(AC)2×2H2O as Se and Zn source, glutathione (GSH) as stabilizing agent and reducing agent. By this approach, the UV‐blue ZnSe QDs with quantum yield (QYs) up to 19% have been synthesized with a molar ratio of Se/Zn/GSH at 1:4:8.5 under aqueous conditions at 110 °C. XRD and TEM show the ZnSe QDs are zinc cubic structure particles with an average diameter of 3–5 nm. 相似文献
18.
YANG Song-tao ZHANG Suo-qin ZHANG Guang-liang WANG Xiao-ming LI Yao-xian 《高等学校化学研究》2007,23(4):426-429
This article presents a novel catalytic method by combining phase-transfer catalyst,benzyltriethylammonium chloride,with 4-dimethylaminopyridine for the syntheses of glycosyl esters from substituted phenoxyacetic acids and the peracetate of α-D-1-bromosugars to produce eight novel β-glycosyl esters in high yields.The structures of the synthesized compounds were established by IR,MS,1H NMR,and 13C NMR spectra and elemental analyses. 相似文献
19.
Qing LI Hui LI Bin SU Xiang Bao MENG Meng Shen CAI Zhong Jun LI* Department of Chemical Biology School of Pharmaceutical Sciences National Research Laboratory of Natural Biomimetic Drugs Peking University Beijing 《中国化学快报》2002,13(4):303-305
Our previous paper1,2reported the results of selective synthesis of mannose type glycosides and their dimers in our attempt to synthesize derivatives of N-acetyllacto- samine, which could have potential activity of anti-metastasis3. Further studies on the glycosylation of the accepters exploiting glycosyl nitrate instead of the acetate as donor showed interesting chemoselectivity between the two kinds of donor, namely, the glucose type and the mannose type. The reactivity difference of the t… 相似文献
20.
《中国化学会会志》2017,64(10):1213-1219
The preparation of bis‐thiazolidinones has been achieved by a one‐pot condensation reaction of araldehydes, ethylenediamine, and 2‐mercaptoacetic acid in the presence of nano‐CuFe2O4@chitosan under reflux conditions in toluene. The catalyst was characterized by powder X‐ray diffraction (XRD), scanning electronic microscopy (SEM), vibrating sample magnetometer (VSM) measurements, thermal gravimetric analysis (TGA), and FT‐IR spectroscopy. This method provides several advantages including excellent yields, wide range of products, reusability of the catalyst, and a low amount of the catalyst. 相似文献