TY  - JOUR
A1  - Pimpalpalle, Tukaram M.
A1  - Yin, Jian
A1  - Linker, Torsten
T1  - Barton radical reactions of 2-C-branched carbohydrates
JF  - Organic & biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry
N2  - 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.
Y1  - 2012
U6  - https://doi.org/10.1039/c1ob06370g
SN  - 1477-0520
VL  - 10
IS  - 1
SP  - 103
EP  - 109
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Vidadala, Srinivasa Rao
A1  - Pimpalpalle, Tukaram M.
A1  - Linker, Torsten
A1  - Hotha, Srinivas
T1  - Gold-Catalyzed reactions of 2-C-Branched carbohydrates mild glycosidations and selective anomerizations
JF  - European journal of organic chemistry
N2  - 2-C-branched methyl glycosides react with various alcohols under gold catalysis to transglycosylated products. The method is applicable for the convenient synthesis of disaccharides. Without nucleophile a selective anomerization occurs, giving first access to alpha-configured 2-C-nitromethyl glycosides. The results are interesting for the mechanism of gold-catalyzed glycosidations.
KW  - Anomerization
KW  - Carbohydrates
KW  - Glycosidation
KW  - Gold
KW  - Synthetic methods
Y1  - 2011
U6  - https://doi.org/10.1002/ejoc.201100134
SN  - 1434-193X
IS  - 13
SP  - 2426
EP  - 2430
PB  - Wiley-Blackwell
CY  - Malden
ER  - 
TY  - JOUR
A1  - Pimpalpalle, Tukaram M.
A1  - Vidadala, Srinivasa Rao
A1  - Hotha, Srinivas
A1  - Linker, Torsten
T1  - Lewis acid-catalyzed stereoselective lactonization and subsequent glycosidation of 2-C-malonyl carbohydrates
JF  - Chemical communications
N2  - Gold(III) bromide is a suitable catalyst for the stereoselective cyclization of 2-C-malonyl carbohydrates to the anomeric center under retention of one ester group. Reopening of the lactones with alcohols in the presence of TMSOTf affords allyl, propargyl and benzyl glycosides with high alpha-selectivity.
Y1  - 2011
U6  - https://doi.org/10.1039/c1cc13425f
SN  - 1359-7345
VL  - 47
IS  - 37
SP  - 10434
EP  - 10436
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Wang, Xuebin
A1  - Wang, Xiaoli
A1  - Hu, Jing
A1  - Wang, Zhaoya
A1  - Pimpalpalle, Tukaram M.
A1  - Linker, Torsten
A1  - Yin, Jian
T1  - Study on the Synthesis of Novel Sugar Amino Acids
T1  - 新型糖氨基酸类化合物的合成研究
JF  - Acta chimica Sinica = Huaxue-xuebao
N2  - 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.
KW  - sugar amino acids
KW  - glycal
KW  - radical addition
KW  - one-pot reaction
KW  - synthesis
Y1  - 2015
U6  - https://doi.org/10.6023/A15030205
SN  - 0567-7351
VL  - 73
IS  - 7
SP  - 699
EP  - 704
PB  - Science China Press
CY  - Beijing
ER  -