Protecting Group Dependence of Stereochemical Outcome of Glycosylation of 2-O-(Thiophen-2-yl)methyl Ether Protected Glycosyl Donors

2016 ◽  
Vol 2016 (8) ◽  
pp. 1520-1532 ◽  
Author(s):  
Andrew J. A. Watson ◽  
Stewart R. Alexander ◽  
Daniel J. Cox ◽  
Antony J. Fairbanks
Keyword(s):  
Methyl Ether ◽  
Protecting Group ◽  
Glycosyl Donors

Stereoselective Synthesis of Diglycosyl Diacylglycerols with Glycosyl Donors Bearing a β-Stereodirecting 2,3-Naphthalenedimethyl Protecting Group

2020 ◽  
Vol 85 (24) ◽  
pp. 16166-16181
Author(s):  
Nahoko Yagami ◽  
Amol M. Vibhute ◽  
Hide-Nori Tanaka ◽  
Naoko Komura ◽  
Akihiro Imamura ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Protecting Group ◽  
Glycosyl Donors

Metal-catalyzed Stereoselective and Protecting-group-free Synthesis of 1,2-cis-Glycosides Using 4,6-Dimethoxy-1,3,5-triazin-2-yl Glycosides as Glycosyl Donors

2015 ◽  
Vol 44 (6) ◽  
pp. 846-848 ◽  
Author(s):  
Tomonari Tanaka ◽  
Naoya Kikuta ◽  
Yoshiharu Kimura ◽  
Shin-ichiro Shoda
Keyword(s):  
Protecting Group ◽  
Metal Catalyzed ◽  
Glycosyl Donors

scholarly journals Direct amidation of unprotected amino acids using B(OCH2CF3)3

2016 ◽  
Vol 52 (57) ◽  
pp. 8846-8849 ◽  
Author(s):  
Rachel M. Lanigan ◽  
Valerija Karaluka ◽  
Marco T. Sabatini ◽  
Pavel Starkov ◽  
Matthew Badland ◽  
...  
Keyword(s):  
Amino Acids ◽  
Methyl Ether ◽  
Protecting Group ◽  
Borate Ester ◽  
Direct Amidation

A commercially available borate ester, B(OCH2CF3)3, can be used to achieve protecting-group free direct amidation of α-amino acids with a range of amines in cyclopentyl methyl ether.

New Effective Synthesis of (N-Acetyl- and N-Stearoyl-2-amino-2-deoxy-β-D-glucopyranosyl)-(1→4)-N-acetylnormuramoyl-L-2-aminobutanoyl-D-isoglutamine, Analogs of GMDP with Immunopotentiating Activity

1998 ◽  
Vol 63 (4) ◽  
pp. 577-589 ◽  
Author(s):  
Miroslav Ledvina ◽  
Daniel Zyka ◽  
Jan Ježek ◽  
Tomáš Trnka ◽  
David Šaman
Keyword(s):  
Protecting Group ◽  
Silver Triflate ◽  
Effective Synthesis ◽  
Methyl Triflate ◽  
Glycosyl Donors

Ethyl 3,4,6-tri-O-benzyl-2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside (5), prepared by benzylation of ethyl 2-deoxy-2-phthalimido-1-thio-β-D-glucopyranoside (4), was transformed by reaction with bromine into 3,4,6-tri-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl bromide (6). Thioglycoside 5 in the presence of methyl triflate and glycosylbromide 6 in the presence of silver triflate were used as glycosyl donors for condensation with benzyl 2-acetamido-3-O-allyl-6-O-benzyl-2-deoxy-α-D-glucopyranoside (7), to give benzyl 2-acetamido-3-O-allyl-6-O-benzyl-4-O-(3,4,6-tri-O-benzyl-2-deoxy-2-phthalimido-β-D-glucopyranosyl)-2-deoxy-α-D-glucopyranoside (8). Its reductive dephthaloylation with NaBH4/AcOH afforded benzyl 2-acetamido-3-O-allyl-4-O-(2-amino-3,4,6-tri-O-benzyl-2-deoxy-β-D-glucopyranosyl)- 6-O-benzyl-2-deoxy-α-D-glucopyranoside (11). Compound 11 was N-acylated to give benzyl 2-acetamido-4-O-(2-acylamino-3,4,6-tri-O-benzyl-2-deoxy-β-D-glucopyranosyl)-3-O-allyl-6-O-benzyl-2-deoxy-α-D-glucopyranosides (12a) or (12b). These compounds were converted into corresponding benzyl 2-acetamido-4-O-(2-acylamino-3,4,6-tri-O-benzyl-2-deoxy-β-D-glucopyranosyl)-6-O-benzyl-3-O-carboxymethyl-2-deoxy-α-D-glucopyranosides which, by condensation with H-L-Abu-D-isoGln(OBzl) followed by hydrogenolysis of protective benzyl groups, furnished glycopeptides 16a and 16b. Intramolecular O→N migration of the allyl protecting group followed by its reduction to the propyl residue by reaction of compound 8 with hydrazine or hydrazinium acetate, to give benzyl 2-acetamido-4-O-(3,4,6-tri-O-benzyl-2-deoxy-2-propylamino-β-D-glucopyranosyl)-6-O-benzyl-2-deoxy-α-D-glucopyranoside (9), is also described.

Synthesis of Structurally Simplified Aureolic Acid Aglycone-C-D-E Trisaccharide Analogues

2002 ◽  
Vol 55 (2) ◽  
pp. 113 ◽  
Author(s):  
W. R. Roush ◽  
N. A. Powell ◽  
R. A. James
Keyword(s):  
Dna Binding ◽  
Complex Formation ◽  
Deoxyribonucleic Acid ◽  
Single Step ◽  
Protecting Group ◽  
Acetate Ester ◽  
Aureolic Acid ◽  
Glycosyl Donors

Syntheses of aureolic acid analogues (5) and (6) with (2S)- and (2R)-acyloin stereochemistry, respectively, are described. The synthesis of (5) utilizes a `C + DE' glycosidation sequence, whereas analogue (6), with unnatural (2R)-acyloin stereochemistry, was synthesized by a sequence in which the entire C-D-E trisaccharide was introduced in a single step. While these syntheses provided sufficient quantities of the two aureolic acid analogues for use in studies of Mg2+ complex formation and deoxyribonucleic acid (DNA) binding, this work also highlights certain limitations in the use of 2-thiophenyl glycosyl donors for synthesis of 2-deoxy-β-glycosides. Specifically, difficulties were encountered in the identification of a protecting group for the aglycone C8 phenol that is fully compatible with the conditions required for reductive removal of the thiophenyl substituents after completion of the glycosidation sequence. Sensitivity of the C2 acyloin stereocentre to the conditions required for deprotection of a phenolic acetate ester are also highlighted in the syntheses of (5), and especially of (6).

ChemInform Abstract: 2,4-Dimethoxybenzyl: An Amide Protecting Group for 2-Acetamido Glycosyl Donors.

ChemInform ◽  
2010 ◽  
Vol 33 (19) ◽  
pp. no-no
Author(s):  
Nicholas M. Kelly ◽  
Knud J. Jensen
Keyword(s):  
Protecting Group ◽  
Glycosyl Donors

Iron(iii) chloride modulated selective 1,2-trans glycosylation based on glycosyl trichloroacetimidate donors and its application in orthogonal glycosylation

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105589-105606 ◽  
Author(s):  
Mana Mohan Mukherjee ◽  
Nabamita Basu ◽  
Rina Ghosh
Keyword(s):  
Protecting Group ◽  
Glycosyl Donors

FeCl3 modulated excellent 1,2-trans selective glycosylations based on trichloroacetimidate glycosyl donors even in the presence of apparently silent C-2 protecting group, along with orthogonal glycosylation reactions are reported.

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