Substrate Specificity and Preparative Use of Recombinant Rat ST3Gal III
摘要:
Recombinant rat alpha(2-->3)-sialyltransferase (ST3Gal III, EC 2.4.99.6) was expressed from baculovirus infected Sf 9 insect cells in preparative amounts. In order to elucidate substrate tolerances of ST3Gal III, the natural type I and type II substrates 21 and 22 as well as several non-natural sugars were investigated. The non-natural Gal-beta(1 --> 3)Gal-(N) (type III) disaccharides 11, 13, and 16 turned out to be surprisingly good substrates for ST3Gal III. All sialylations were run in preparative scale and kinetic parameters (V-max and K-m) were determined.
Koenigs–Knorr Glycosylation Reaction Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
作者:Yashapal Singh、Alexei V. Demchenko
DOI:10.1002/chem.201805527
日期:2019.1.28
The discovery that traditional silver(I)‐oxide‐promoted glycosidations of glycosyl bromides (Koenigs–Knorr reaction) can be greatly accelerated in the presence of catalytic trimethylsilyl trifluoromethanesulfonate (TMSOTf) is reported. The reaction conditions are very mild that allowed for maintaining a practically neutral pH and, at the same time, providing high rates and excellent glycosylation yields
作者:Yashapal Singh、Tinghua Wang、Scott A. Geringer、Keith J. Stine、Alexei V. Demchenko
DOI:10.1021/acs.joc.7b02768
日期:2018.1.5
Previously, we communicated 3,3-difluoroxindole (HOFox)-mediated glycosylations wherein 3,3-difluoro-3H-indol-2-yl (OFox) imidates were found to be key intermediates. Both the in situ synthesis from the corresponding glycosyl bromides and activation of the OFox imidates could be conducted in a regenerative fashion. Herein, we extend this study to the synthesis of various glycosidic linkages using different