Facile synthesis of urea-and thiocarbamate-tethered glycosyl beta-amino acids†
Abstract
We describe here an efficient way to synthesize series of new urea- and thiocarbamate-tethered glycosyl β-amino acids under mild conditions. These glycosyl β-amino acids are elaborately designed on the basis of natural N-linked glycosides. They have the same side chain length as natural N-glycosyl amino acid while the main chain is replaced with β-amino acid chain. The linkage is an isostere of natural N-linked bond but exhibits competitive stability to chemical and enzymatic hydrolysis. This facile route is benefit from the choice of the commercially available L-aspartic acid as starting material, which not only provides a β-amino acid moiety, but also the α-carboxy group could be transformed to active isocyanate conveniently and economically. The prospective glycosyl β-amino acids are obtained readily by the reaction of isocyanate with appropriately protected glycosylamines and glycosylthiols.