Glycopeptide mimetics

Figure 14.4 Bound conformation of the SLex tetrasaccharide compared to that of an efficient fucosyl glycopeptide mimetic compound.81 Tightly bound hydroxyl groups are shown as spheres.

Complex-type W-linked glycopeptide mimetics by Bertozzi and co-workers... 

Another potential avenue to the constmction of glycopeptide mimetics is through chemoselective ligation of functional groups with matched reactivities. Cervigni et al. have report-... 

The glycopeptide mimetic structure was found to have antibacterial activity that exceeded that of the unglycosylated drosocin construct. As such, the authors concluded that altered carbohydrate structure outside of the conserved glycosyl-peptide bond was a tolerated modification in the biological system. 

This elaborated methodology should provide an easy access to glycopeptide mimetics. To demonstrate that we reacted maltose 124 as an example for the deployment of disaccharides in these cascade reactions (Scheme 2.25), the expected lactone 125 was isolated with 33% yields after 3 h in refluxing methanol. These yields are comparable with those obtained in reactions of glucose with L-proline and ethyl isocyanoacetate (114 36% Scheme 2.23). But an increase in syn-selectivity was detected, indicating further supporting hydrogen bonds (compare 114 60/40 with 125 83/17). 

Mahrwald and coworkers [14] reported a new synthetic approach to carbohydrate heterocycles via three-component reactions starting from unprotected maltose, L-proline, and ethyl isocyanoacetate. The process is catalyzed by N,N-diisopropylethylamine (Huning s base) and produces glycopeptide mimetic as functionalized lactone, which was isolated in a 36% yield as syn/anti mixture 83/17. The methodology is depicted in Scheme 6.10. 

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