Synthesis of azathia-analogues of platelet activating factor containing a methioninol backbone

The synthesis of azathia-analogues of the platelet activating factor containing a methioninol backbone is reported. The preparation starts with a cylating methionine ethyl ester-HCl with palmitoyl chloride to form the amide linkage. Following ester reduction the phosphocholine part is introduced via 2-chloro-2-oxo-1,3,2-dioxaphospholane and subsequent ring opening with trimethylamine under pressure. Two related compounds, the sulfoxide and the sulfone, are obtained by oxidation with 3-chloroperbencoic acid. In addition the sulfoxide derivative is prepared starting with d - and l -methionine ethyl ester-HCl.