Synthesis of some second-generation substrate analogues of early intermediates in the biosynthetic pathway of glycosylphosphatidylinositol membrane anchors

1-d-6-O-(2-Amino-2-deoxy-α-d-glucopyranosyl)-2-O-octyl-myo-inositol 1-(1,2-di-O-hexadecanoyl-sn-glycerol 3-phosphate) (23) and the corresponding 2-O-hexadecyl-d-myo-inositol compound 24 have been prepared as substrate analogues of an early intermediate in the biosynthetic pathway of glycosylphosphatidylinositol (GPI) membrane anchors. 1-d-6-O-(2-Amino-2-deoxy-α-d-glucopyranosyl)-myo-inositol 1-(1,2-di-O-octyl-sn-glycerol 3-phosphate) has also been prepared as a substrate analogue. Biological evaluation of the analogues 23 and 24 revealed that they are neither substrates nor inhibitors of GPI biosynthetic enzymes in the human (HeLa) cell-free system but are potent inhibitors at different stages of GPI biosynthesis in the Trypanosoma brucei cell-free system.