Tokyo Chemical Industry Co. Ltd.

LacdiNAc (GalNAcβ1-4GlcNAc) is a distinctive epitope found at the non-reducing termini of both N- and O-glycans. In recent years, the physiological functions of LacdiNAc have attracted increasing attention. Consequently, there is a significant demand for pure glycans for use in biochemical experiments. In this study, a concise and practical synthetic approach was developed for biantennary complex-type nonasaccharide 1, which contains LacdiNAc structures at the non-reducing end. Specifically, nonasaccharide 2 was initially constructed in a stereoselective manner via the condensation of trisaccharide donor 3 with trisaccharide acceptor 4, which bears hydroxy groups at the 3- and 6-positions of the β-mannose residue. Notably, this was achieved via the remote neighboring group participation of a pivaloyl group. Subsequent conversion of the N-phthalimido group into an acetamido group, followed by global deprotection, furnished the target compound, 1. The developed synthetic route represents a valuable tool for future investigations into LacdiNAc-modified N-glycans.

Selective and large-scale synthesis of [8]cycloparaphenylene (CPP) was achieved in seven steps starting from commercially available 4-bromo-4'-hydroxybiphenyl and 4,4'-dibromobiphenyl. The key unsymmetrical tetraring unit, 4-bromophenyl and 4'-bromobiphenyl-substituted cis-1,4-bis(triethylsiloxy)-2,5-cyclohexadiene-1,4-diyl (5fA), was synthesized on an ∼50 g scale by stereoselective cis-addition of 4-bromo-4'-lithiobiphenyl to 4-(4-bromophenyl)-4-hydroxy-2,5-cyclohexadien-1-one, which was synthesized on an ∼100 g scale. Platinum-mediated selective dimerization of the four-ring unit 5fB and subsequent reductive aromatization of the cyclohexadiene-diyl by H₂SnCl₄ gave 2 g of [8]CPP in 6.6% overall yield (10.2% on small scale).

The antibody preparation method to the glycolipid is basically same to the method to the protein. However, because the immunogenicity of the carbohydrate moieties of glycolipid is generally low in the mouse, the development of the anti-glycolipid antibody using purified glycolipid as an immunogen was not yet established. Here, we describe a method using a purified ganglioside adsorbed onto Salmonella minnesota for the efficient production of an anti-ganglioside mouse monoclonal antibody that recognizes the carbohydrate moieties of the ganglioside.