Synthesis and biological evaluation of four stereoisomers of PDMP-analogue, N-(2-decylamino-3-hydroxy-3-phenylprop-1-yl)-β-valienamine, and related compounds

All stereoisomers with regard to C-1 and 2 of 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) analogue containing unsaturated (β-valienamine) and saturated 5a-carba-β- -glucopyranosylamine (β-validamine) residues in place of morpholine moiety were synthesized. Although PDMP is a potent and specific glucosylceramide synthase inhibitor, the former valienamine analogues (4a-d) have been shown to be strong glucocerebrosidase inhibitors (IC50 3–7 *x 10−7 M). The latter validamine analogues (5a-d) were also moderate glucocerebrosidase inhibitors (IC50 5–20 *x 10−6 M). A series of compounds synthesized lacked an inhibitory potency against the glucosyltransferase at all. Whereas the analogue 6a composed of epimeric α-valienamine residue did not possess any potency against both enzymes.