187160-81-2Relevant academic research and scientific papers
Linear synthesis of a protected H-type II pentasaccharide using glycosyl phosphate building blocks
Love, Kerry Routenberg,Andrade, Rodrigo B.,Seeberger, Peter H.
, p. 8165 - 8176 (2007/10/03)
A linear synthesis of a fully protected H-type II blood group determinant pentasaccharide utilizing glycosyl phosphate and glycosyl trichloroacetimidate building blocks is reported. Envisioning an automated solid-phase synthesis of blood group determinants, the utility of glycosyl phosphates in the stepwise construction of complex oligosaccharides, such as the H-type II antigen, is demonstrated. Installation of the central glucosamine building block required the screening of a variety of nitrogen protecting groups to ensure good glucosamine donor reactivity and protecting group compatibility. The challenge to differentiate C2 of the terminal galactose in the presence of other hydroxyl and amine protecting groups prompted us to introduce the 2-(azidomethyl)benzoyl group as a novel mode of protection for carbohydrate synthesis. The compatibility of this group with traditionally employed protecting groups was examined, as well as its use as a C2 stereodirecting group in glycosylations. The application of the 2-(azidomethyl)benzoyl group along with a systematic evaluation of glycosyl donors allowed for the completion of the pentasaccharide and provides a synthetic strategy that is expected to be generally amenable to the solid support synthesis of blood group determinants.
N-tetrachlorophthaloyl (TCP) for ready protection/deprotection of amino sugar glycosides
Debenham, John S.,Debenham, Sheryl D.,Fraser-Reid, Bert
, p. 1909 - 1918 (2007/10/03)
The tetrachlorophthaloyl (TCP) group can be utilized when imidic protection of an amine is desired and durability of the protecting group to conditions ranging from mildly basic to harshly acidic is required. Installation can be accomplished in two steps by treating the free base with the commercially available TCP anhydride, and then closing the imidic ring with acetic anhydride and pyridine. Cleavage is effected by 2-4 eq of ethylenediamine under very mild conditions under which esters and glycopeptides have been shown to be stable, and racemization of amino acid residues does not occur. Unsubstituted phthalimides, even within the same molecule, are also unaffected during TCP cleavage. TCP protecting groups serve as β-directors on donors and can also be present on acceptor species during electrophilic couplings in oligosaccharide synthesis.
