Synthesis and Structural Characterization of Three Unique <i>Helicobacter pylori</i> α<i>‐</i>Cholesteryl Phosphatidyl Glucosides

Abstract

Abstract Steryl glycosides produced by bacteria play important biological roles in the evasion and modulation of host immunity. Step‐economical syntheses of three cholesteryl‐6‐ O ‐phosphatidyl‐α‐ D ‐glucopyranosides (αCPG) unique to Helicobacter pylori have been achieved. The approach relies upon regioselective deprotection of per‐ O ‐trimethylsilyl‐α‐ D ‐cholesterylglucoside at C6 followed by phosphoramidite coupling. Global TMS ether deprotection in the presence of oxygen and subsequent deprotection of the cyano ethyl phosphoester afforded the target compounds in 16–21 % overall yield starting from D ‐glucose. The structures of these natural products were determined using a combination of 2D NMR methods and mass spectrometry. These robust synthesis and characterization protocols provide analogues to facilitate glycolipidomic profiling and biological studies.