scholarly journals Application of the Superarmed Glycosyl Donor to Chemoselective Oligosaccharide Synthesis

2008 ◽  
Vol 10 (11) ◽  
pp. 2107-2110 ◽  
Author(s):  
Laurel K. Mydock ◽  
Alexei V. Demchenko
Keyword(s):  
Oligosaccharide Synthesis ◽  
Glycosyl Donor

A novel glycosyl donor for chemo-enzymatic oligosaccharide synthesis: 4,6-dimethoxy-1,3,5-triazin-2-yl glycoside

2008 ◽  
pp. 2016 ◽  
Author(s):  
Tomonari Tanaka ◽  
Masato Noguchi ◽  
Atsushi Kobayashi ◽  
Shin-ichiro Shoda
Keyword(s):  
Oligosaccharide Synthesis ◽  
Glycosyl Donor

ChemInform Abstract: A Novel Glycosyl Donor for Chemo-Enzymatic Oligosaccharide Synthesis: 4,6-Dimethoxy-1,3,5-triazin-2-yl Glycoside.

ChemInform ◽  
2008 ◽  
Vol 39 (35) ◽  
Author(s):  
Tomonari Tanaka ◽  
Masato Noguchi ◽  
Atsushi Kobayashi ◽  
Shin-ichiro Shoda
Keyword(s):  
Oligosaccharide Synthesis ◽  
Glycosyl Donor

Glycosylation by Alkyne Activation of the 2-O-Substituted Propargyl Group in a β-Phenylthioglucoside with a 5 S 1 Conformation

Synlett ◽  
2021 ◽  
Author(s):  
Kazutada Ikeuchi ◽  
Shintaro Matsumoto ◽  
Daiki Ikuta ◽  
Hidetoshi Yamada
Keyword(s):  
Hydroxy Group ◽  
Oligosaccharide Synthesis ◽  
Reaction Proceeds ◽  
Oxocarbenium Ion ◽  
Glycosyl Donor ◽  
Glycosylation Reaction

AbstractGenerally, glycosylation reactions activate an anomeric substituent in a glycosyl donor to generate an oxocarbenium ion intermediate. Here we report a novel glycosylation reaction triggered by the activation of a 2-O-substituted propargyl group in a 3,6-O-1,1′-[(ethane-1,2-diyl)bibenzene-2,2′-bis(methylene)]-β-thioglucoside. This reaction proceeds through a cationic Au(I)-mediated intramolecular migration of the anomeric substituent onto the alkyne moiety of the propargyl group, followed by α-attack by the hydroxy group in the glycosyl acceptor on the oxocarbenium ion. The migration of the anomeric group occurs selectively through a 6-exo-dig pathway. The 2-(phenylsulfanyl)prop-2-en-1-yl group produced during the glycosylation is removable under conditions similar to those used for removing an allyl group. This reaction will be developed for further applications in orthogonal oligosaccharide synthesis.

scholarly journals A One-Pot Approach to Novel Pyridazine C-Nucleosides

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2341
Author(s):  
Flavio Cermola ◽  
Serena Vella ◽  
Marina DellaGreca ◽  
Angela Tuzi ◽  
Maria Rosaria Iesce
Keyword(s):  
Organic Chemistry ◽  
Research Field ◽  
Modified Nucleosides ◽  
Protecting Groups ◽  
Coupling Reactions ◽  
One Pot ◽  
Pharmacological Interest ◽  
Classical Methodology ◽  
Glycosyl Donor ◽  
Neutral Conditions

The synthesis of glycosides and modified nucleosides represents a wide research field in organic chemistry. The classical methodology is based on coupling reactions between a glycosyl donor and an acceptor. An alternative strategy for new C-nucleosides is used in this approach, which consists of modifying a pre-existent furyl aglycone. This approach is applied to obtain novel pyridazine C-nucleosides starting with 2- and 3-(ribofuranosyl)furans. It is based on singlet oxygen [4+2] cycloaddition followed by reduction and hydrazine cyclization under neutral conditions. The mild three-step one-pot procedure leads stereoselectively to novel pyridazine C-nucleosides of pharmacological interest. The use of acetyls as protecting groups provides an elegant direct route to a deprotected new pyridazine C-nucleoside.

scholarly journals β-Galactosidase-Producing Isolates in Mucoromycota: Screening, Enzyme Production, and Applications for Functional Oligosaccharide Synthesis

2021 ◽  
Vol 7 (3) ◽  
pp. 229
Author(s):  
Bettina Volford ◽  
Mónika Varga ◽  
András Szekeres ◽  
Alexandra Kotogán ◽  
Gábor Nagy ◽  
...  
Keyword(s):  
Wheat Bran ◽  
Enzyme Production ◽  
Specific Activity ◽  
Prebiotic Synthesis ◽  
Crude Enzyme ◽  
Oligosaccharide Synthesis ◽  
Industrial Enzymes ◽  
Chromogenic Agar ◽  
Lichtheimia Ramosa ◽  
Excellent Source

β-Galactosidases of Mucoromycota are rarely studied, although this group of filamentous fungi is an excellent source of many industrial enzymes. In this study, 99 isolates from the genera Lichtheimia, Mortierella, Mucor, Rhizomucor, Rhizopus and Umbelopsis, were screened for their β-galactosidase activity using a chromogenic agar approach. Ten isolates from the best producers were selected, and the activity was further investigated in submerged (SmF) and solid-state (SSF) fermentation systems containing lactose and/or wheat bran substrates as enzyme production inducers. Wheat bran proved to be efficient for the enzyme production under both SmF and SSF conditions, giving maximum specific activity yields from 32 to 12,064 U/mg protein and from 783 to 22,720 U/mg protein, respectively. Oligosaccharide synthesis tests revealed the suitability of crude β-galactosidases from Lichtheimia ramosa Szeged Microbiological Collection (SZMC) 11360 and Rhizomucor pusillus SZMC 11025 to catalyze transgalactosylation reactions. In addition, the crude enzyme extracts had transfructosylation activity, resulting in the formation of fructo-oligosaccharide molecules in a sucrose-containing environment. The maximal oligosaccharide concentration varied between 0.0158 and 2.236 g/L depending on the crude enzyme and the initial material. Some oligosaccharide-enriched mixtures supported the growth of probiotics, indicating the potential of the studied enzyme extracts in future prebiotic synthesis processes.

scholarly journals Cold-Active β-Galactosidases: Insight into Cold Adaption Mechanisms and Biotechnological Exploitation

Marine Drugs ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 43
Author(s):  
Marco Mangiagalli ◽  
Marina Lotti
Keyword(s):  
Low Temperature ◽  
Molecular Mechanisms ◽  
Building Blocks ◽  
Cold Active ◽  
Cold Adaption ◽  
Glycosyl Donor ◽  
Pharmaceutical Industries ◽  
Biotechnological Processes ◽  
Hydrolysis Of ◽  
Insight Into

β-galactosidases (EC 3.2.1.23) catalyze the hydrolysis of β-galactosidic bonds in oligosaccharides and, under certain conditions, transfer a sugar moiety from a glycosyl donor to an acceptor. Cold-active β-galactosidases are identified in microorganisms endemic to permanently low-temperature environments. While mesophilic β-galactosidases are broadly studied and employed for biotechnological purposes, the cold-active enzymes are still scarcely explored, although they may prove very useful in biotechnological processes at low temperature. This review covers several issues related to cold-active β-galactosidases, including their classification, structure and molecular mechanisms of cold adaptation. Moreover, their applications are discussed, focusing on the production of lactose-free dairy products as well as on the valorization of cheese whey and the synthesis of glycosyl building blocks for the food, cosmetic and pharmaceutical industries.

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