S-Glycosylation

Synthesis and Preliminary Evaluation of Biological Activity of Glycoconjugates Analogues of Acyclic Uridine Derivatives

“…While the synthesis of 1-β thiosugars is relatively simple to carry out and leads to the desired compounds at a high yield, the synthesis of analogues of the α-configuration poses many difficulties. However numerous reports for the α-glycosylthiol derivatives synthesis have appeared in the literature [ 40 ]. Although most of the reaction conditions described suffer from several limitations, including formation of mixture of isomers, multiple reaction and/or purification steps, long reaction time, low yield, use of hazardous gases (e.g., H 2 S), use of expensive reagents (e.g., (TMS) 2 S), necessity of use of appropriately functionalised substrates, etc.…”

“…Corresponding glycosylthiols are easy to obtain by alcoholysis and can be used for the preparation of heteroaryl 1-thioglycosides. Among the numerous methods of synthesising 1-thioglycosides described in the literature [ 40 ], for the synthesis of (5-nitro-2-pyridyl) 1-thioglycosides, the procedure of aromatic substitution of nucleophilic halogen in negatively substituted aryl derivatives [ 44 ] was used. Treatment of the 2,3,4,6-tetra- O -benzyl-1-thio- d -gluco- or 2,3,4,6-tetra- O -benzyl-1-thio- d -galactopyranose with 2-chloro-5-nitropyridine gives corresponding heteroaryl thioglycosides.…”

Automated Chemical Oligosaccharide Synthesis: Novel Approach to Traditional Challenges

“…115 Thus, in the 1970’s to early 1980’s, a few new classes of glycosyl donors were developed. 116,117 This first wave introduced thioglycosides, 118–121 1,2-orthoesters, 122,123 O -imidates, 124,125 thioimidates, 126–128 and glycosyl fluorides 129 as alternative leaving groups. Many glycosyl donors introduced during that period have become common even to this day.…”

General Aspects of the Glycosidic Bond Formation

“…During the 1970s to early 1980s, a few new classes of glycosyl donors were developed. The following compounds are only the most representative examples of the first wave of the leaving-group development: thioglycosides by Ferrier et al [17], Nicolaou et al [18], Garegg et al [19] and others [20]; cyanoethylidene and orthoester derivatives by Kochetkov and coworkers [21,22]; O-imidates by Sinay and coworkers [23] and Schmidt and Michel [24]; thioimidates including S-benzothiazolyl derivatives by Mukaiyama et al [25]; thiopyridyl derivatives by Hanessian et al [26] and Woodward et al [27] and glycosyl fluorides by Mukaiyama et al [28] (Figure 1.2). Many glycosyl donors introduced during that period gave rise to excellent complimentary glycosylation methodologies.…”