173977-53-2Relevant academic research and scientific papers
Glycosyl Imidates, 73. Synthesis of Ganglioside GM1 via a GA1 Intermediate
Stauch, Thomas,Greilich, Ulrike,Schmidt, Richard R.
, p. 2101 - 2112 (2007/10/03)
The synthesis of GM1 pentasaccharide 36 via GA1-intermediate 24 was based on lactose building block 11, Galβ(1-3)GalN3 building block 23, and sialyl donors 32.For the synthesis of 11, tetra-O-acetyl galactosyl trichloroacetimidate 3 or 2,3-di-O-acetyl-4,6-O-benzylidene-galactosyl trichloroacetimidate 5 as donors were allowed to react with 4-O-unprotected glucose derivative 4 as acceptor to afford lactose derivatives 6 and 7, respectively, in high yields.They were readily transformed via 8 into 2b,3b-O-MPM-protected 9; reductive opening of the dioxane ring with DIBAH furnished regioselectively the desired 4b-O-unprotected lactose derivative 11.From donor 3 and 6-O-benzoyl-protected 2-azidoglucose 19 as acceptor Galβ(1-3)GalN3 disaccharide 20 was synthesized which was readily converted into per-O-acyl-protected trichloroacetimidate 23.Reaction of 23 with 11 afforded upon Sn(OTf)2 catalysis the desired β-linked tetrasaccharide 24 in high yield.Removal of the MPM-protective groups with DDQ furnished 2b,3b-O-unprotected derivative 31, which gave by treatment with sialyl donors 32a and 32b GM1-pentasaccharide intermediate 33 in good yield. 2b-O-Acylation and then hydrogenolysis in the presence of Pearlman's catalyst and ensuing peracetylation afforded O-acyl-protected GM1-pentasaccharide 36 which was alredy previously converted into GM1. - Keywords: Glycosylsphingolipids; Ganglio series; Glycoside synthesis; O-Glycosyl trichloroacetimidates; Sialyl phosphite
