Synthetic route for 14C-labeling of a bioactive lipid A analogue

Article abstract of DOI:10.1016/0040-4039(95)01863-D

A synthetic route for ¹⁴C-labeling of a phosphonooxyethyl (PE) analogue of E. coli lipid A was established by cold experiments. The PE analogue is chemically more stable than natural lipid A but shows particularly identical biological activity. The glycosidation of ethylene glycol unit as the ¹⁴C-labeled position was effected with a disaccharide thioglycoside by use of a hypervalent iodine reagent, PhIO-SnClO₄-AgClO₄, as an activator. p-Methoxybenzyl group used for the protection of the distal hydroxyl group of ethylene glycol was selectively removed by trimethylsilyl triflate in CH₃CN-CH₂Cl₂ followed by phosphorylation and deprotection gave the target compound.