1-O-Octadecyl-2-O-benzyl-rac-glycerol-d5 is labelled 1-O-Octadecyl-2-O-benzyl-rac-glycerol (O235950) which is used in the synthesis of alkylphospholipids containing modifications of the phosphocholine moiety with antitumor activities. It is also used to prepare platelet activating factor (PAF) antagonists with modified phosphorylcholine moieties.