Metabolic Isolation, Stereochemical Determination, and Total Synthesis of Predominant Native Cholesteryl Phosphatidyl-α-glucoside from Carcinogenic Helicobacter pylori .

We report the isolation and stereochemical determination of the predominant native cholesteryl 6- O -phosphatidyl α-glucoside (CPG) from Helicobacter pylori via an integrated biological and chemical strategy. The strategy employed (i) the metabolic isolation of a CPG analogue and (ii) the enzymatic degradation of the analogue to obtain the native lactobacillic acid for the stereochemical determination. The absolute stereochemistry of the acid was found to be 11 R and 12 S . Using the new stereochemical data, we accomplished the total synthesis of predominant native CPG and other predominant αCG derivatives.