1: methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-2-S-acetyl-3,5-dideoxy-2-thio-D-glycero-α-D-galacto-non-2-ulopyranosylonate With methanol; sodium T=-40°C; 0.666667 h; 2: methyl iodide in N,N-dimethyl-formamide T=20°C;

1: acetic anhydride, HCl / acetic acid / 16 h 2: acetonitrile / 2 h View Scheme

in acetonitrile 2 h; Title compound not separated from byproducts;

1.1: 90 percent / CH2Cl2 / 20 h / 20 °C 2.1: Na; MeOH / 0.67 h / -40 °C 2.2: 91 percent / dimethylformamide / 20 °C View Scheme

1.1: Dowex 50W-X8-200(H+) / 2 h / 20 °C 1.2: pyridine / 48 h / 20 °C 1.3: 100 percent / HCl gas; AcCl / 20 h / -50 - 20 °C 2.1: 90 percent / CH2Cl2 / 20 h / 20 °C 3.1: Na; MeOH / 0.67 h / -40 °C 3.2: 91 percent / dimethylformamide / 20 °C View Scheme

dimethyl-(methylthio)-sulphonium trifluoromethanesulphonate in acetonitrile T=-15°C; 15 h;