2-DEOXY-1,3,4,5,6-PENTA-O-METHYL-2-(N-METHYLACETAMIDO)-D-GLUCITOL AND DERIVATIVES UNDERGO C-METHYLATION AT THE N-METHYLACETAMIDO GROUP ON REPEATED HAKOMORI METHYLATION

Article abstract of DOI:10.1016/S0008-6215(00)90289-1

After Hakomori methylation of 2-acetamido-2-deoxy-D-glucitol, the expected 2-deoxy-1,3,4,5,6-penta-O-methyl-2-(N-methylacetamido)-D-glucitol (3) was identified by g.l.c.-m.s. as the major product, and two minor products, 2-acetamido-2-deoxy-1,3,4,5,6-penta-O-methyl-D-glucitol (2) and 2-deoxy-1,3,4,5,6-penta-O-methyl-2-(N-methylpropionamido)-D-glucitol (4), were present.The proportions and yields of these products were dependent on the reagent (sodium or potassium hydride) used for the preparation of the methylsulfinylmethanide.On Hakomori methylation of 2 and 3, the N-methylpropionamido (4), N-methylisobutyramido, and traces of the N-methylpivalamido derivatives of 2-deoxy-1,3,4,5,6-penta-O-methyl-D-glucitol were formed.Using trideuteriomethyl iodide for methylation (e.g., of 3), it was found by g.l.c.-m.s. that the newly introduced methyl group(s) were located at the β-carbon of the N-methylacetamido group.Analogous results were obtained with 2-deoxy-4-O-<2-deoxy-3,4,6-tri-O-methyl-2-(N-methylacetamido)-β-D-glucopyranosyl>-1,3,5,6-tetra-O-methyl-2-(N-methylacetamido)-D-glucitol.