@article{TianHuZhangetal.2018, author = {Tian, Guang-Zong and Hu, Jing and Zhang, Heng-Xi and Rademacher, Christoph and Zou, Xiao-Peng and Zheng, Hong-Ning and Xu, Fei and Wang, Xiao-Li and Linker, Torsten and Yin, Jian}, title = {Synthesis and conformational analysis of linear homo- and heterooligomers from novel 2-C-branched sugar amino acids (SAAs)}, series = {Scientific reports}, volume = {8}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-018-24927-6}, pages = {8}, year = {2018}, abstract = {Sugar amino acids (SAAs), as biologically interesting structures bearing both amino and carboxylic acid functional groups represent an important class of multifunctional building blocks. In this study, we develop an easy access to novel SAAs in only three steps starting from nitro compounds in high yields in analytically pure form, easily available by ceric (IV) mediated radical additions. Such novel SAAs have been applied in the assembly of total nine carbopeptoids with the form of linear homo-and heterooligomers for the structural investigations employing circular dichroism (CD) spectroscopy, which suggest that the carbopeptoids emerge a well-extended, left (or right)-handed conformation similar to polyproline II (PPII) helices. NMR studies also clearly demonstrated the presence of ordered secondary structural elements. 2D-ROESY spectra were acquired to identify i+1NH <-> (C1H)-C-i, (C2H)-C-i correlations which support the conformational analysis of tetramers by CD spectroscopy. These findings provide interesting information of SAAs and their oligomers as potential scaffolds for discovering new drugs and materials.}, language = {en} } @article{WangWangHuetal.2015, author = {Wang, Xuebin and Wang, Xiaoli and Hu, Jing and Wang, Zhaoya and Pimpalpalle, Tukaram M. and Linker, Torsten and Yin, Jian}, title = {Study on the Synthesis of Novel Sugar Amino Acids}, series = {Acta chimica Sinica = Huaxue-xuebao}, volume = {73}, journal = {Acta chimica Sinica = Huaxue-xuebao}, number = {7}, publisher = {Science China Press}, address = {Beijing}, issn = {0567-7351}, doi = {10.6023/A15030205}, pages = {699 -- 704}, year = {2015}, abstract = {Sugar amino acids (SAAs) are carbohydrate derivatives bearing both amino and carboxylic acid functional groups. SAAs represent an important class of multifunctional building blocks, which are amenable to serve as glycomimetics or peptidomimetics with well-defined structures and useful properties. Because SAAs exist in nature in many forms with various biological activities, recently, many unnatural SAAs, as the demand for finding new molecules to discover new drugs and new materials, have been designed and synthesized by a number of research groups. In this paper, we have developed a convenient method for the synthesis of novel SAAs gluco-7 and galacto-7 for the first time. The structure of gluco-7 was similar to the natural SAA glucosaminuronic acid that was a component of many typical bacterial cell walls and could be used for the preparation of type D flu vaccine; while galacto-7 was similar to the natural SAA galactosaminuronic acid that was one of bacterial Vi-antigen components of Escherichia coli. Starting from unexpensive and commercially available 3,4,6-tri-O-acetyl-D-glucal and 3,4,6-tri-O-acetyl-D-galactal, two novel SAAs gluco-7 and galacto-7 were achieved in the linear 6 steps with 34\% overall yield and 19\% overall yield, respectively. The key reactions included radical addition, decarboxylation, iodine generation reaction, azide reaction and reductive amination reaction. The crucial step was the synthesis of the target compound gluco-7 from gluco-6. By using method A, the target compound gluco-7 was obtained in 4 steps with 63\% overall yield. To optimize the transformation from gluco-6 to gluco-7, method B was developed to generate gluco-7 by using one-pot reaction successfully with 76\% yield only in one step. It proved that method B was superior to method A with shorter steps and higher yields. All the new compounds were characterized by IR, H-1 NMR, C-13 NMR and HRMS data. Study on the synthesis and biological evaluation of linear and cyclic oligomers derived from gluco-7 and galacto-7 are currently in progress.}, language = {zh} } @article{YinLinker2011, author = {Yin, Jian and Linker, Torsten}, title = {Stereoselective diversity-oriented syntheses of functionalized saccharides from bicyclic carbohydrate 1,2-lactones}, series = {Tetrahedron}, volume = {67}, journal = {Tetrahedron}, number = {13}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2011.01.069}, pages = {2447 -- 2461}, year = {2011}, abstract = {Bicyclic carbohydrate 1,2-lactones have been synthesized in only two steps and high yields by saponification and subsequent cyclization from known malonate addition products to glycals. The gluco-configured lactone serves as an important precursor for diversity-oriented syntheses. Thus, stereoselective opening of the lactone ring was realized with various nucleophiles in the presence of Sc(OTf)(3). This enabled the introduction of different substituents at the anomeric position, to afford a broad variety of 1-functionalized carbohydrates. On the other hand, stereoselective alpha-substitution of the gluco-configured lactone with different electrophiles and subsequent ring opening gives a collection of 2-functionalized saccharides. More than 30 products have been isolated in analytically pure form, and their configurations were unequivocally established by various NMR methods. Thus, carbohydrate 1,2-lactones are attractive precursors for the stereoselective synthesis of diverse saccharides.}, language = {en} } @article{PimpalpalleYinLinker2012, author = {Pimpalpalle, Tukaram M. and Yin, Jian and Linker, Torsten}, title = {Barton radical reactions of 2-C-branched carbohydrates}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {10}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {1}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c1ob06370g}, pages = {103 -- 109}, year = {2012}, abstract = {Barton esters have been introduced into the side chain of carbohydrates with high yields in only a few steps from easily available glycals. Their radical reactions afford 2-C-methyl and 2-C-bromomethyl hexoses, pentoses and disaccharides in good yields in analytically pure form. Since the Barton esters have been synthesized by an oxidative radical addition and their transformations by reductive radical processes, our results demonstrate the power of such reactions in carbohydrate chemistry.}, language = {en} } @article{YinLinker2012, author = {Yin, Jian and Linker, Torsten}, title = {Recent advances in the stereoselective synthesis of carbohydrate 2-C-analogs}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {10}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {12}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c2ob06529k}, pages = {2351 -- 2362}, year = {2012}, abstract = {C-branched carbohydrates are of current interest for glycochemistry, are widely found in nature and serve as important subunits in many antibiotics, bacterial polysaccharides and macrolides. Among C-functionalized saccharides, 2-C-branched carbohydrates represent challenging structures for synthetic chemists, since in contrast to C-glycosides they are not easily accessible from glycosyl bromides or other simple precursors. In this perspective we want to summarize recent approaches to 2-C-branched carbohydrates over the past fifteen years. The two main strategies are based on ring-opening of 1,2-cyclopropanated carbohydrates by various reagents, as well as radical additions to glycals and further transformations, developed in our group. Both methods are characterized by high stereoselectivities and good yields and give access to a broad variety of functionalized carbohydrate 2-C-analogs.}, language = {en} } @article{YinLinker2009, author = {Yin, Jian and Linker, Torsten}, title = {Stereodivergent syntheses at the glucose backbone}, issn = {1477-0520}, doi = {10.1039/B918893m}, year = {2009}, abstract = {Both diastereomers of 2-C-branched carbohydrates with various functional groups are selectively available from the same malonate precursor in good yields in only a few steps.}, language = {en} } @article{YinLinker2009, author = {Yin, Jian and Linker, Torsten}, title = {Convenient synthesis of bicyclic carbohydrate 1,2-lactones and their stereoselective opening to 1- functionalized glucose derivatives}, issn = {0947-6539}, doi = {10.1002/chem.200802178}, year = {2009}, abstract = {Closed and re-opened for business: C-2 branched carbohydrates 1 cyclize under conditions of decarboxylation to the hitherto unknown carbohydrate 1,2-lactones 2 in high yields. The gluco isomer can be opened at the anomeric position with various nuceophiles in the presence of Sc(OTf)3, which allows the stereoselective synthesis of 1-functionalized glucose derivatives 3. Thus, 1,2-bis-C-branched saccharides become available in only a few steps starting from glycals.}, language = {en} } @phdthesis{Yin2009, author = {Yin, Jian}, title = {Syntheses and transformations of 2-C-Malonyl substituted carbohydrates}, address = {Potsdam}, pages = {XII, 133 S. _ graph. Darst.}, year = {2009}, language = {en} }