within this membrane other preferred compounds may be those in which y represents a group where u201c polymer u201d designates a natural or synthetic biocompatible polymer having a molecular weight of 10 3 10 6 like heparin hyaluronic acid dextran carboxymethylcellulose chondroitin sulfate dermatan sulfate polyethyleneglycol peptides or proteins such polymeric compounds of the invention are unable to penetrate the cell membrane and enter the cells and will thus enable inhibition only at the outer cell membrane or extracellular surroundings as shown in the following examples the novel synthetic compounds of the invention are capable of inhibiting degradation as well as biosynthesis of sphingolipids as such these compounds may be used in the treatment of lipidoses particularly genetic lipid storage diseases in which sphingolipids accumulate in organs of afflicted patients such as gaucher disease tay sachs disease niemann pick disease krabbe disease metachromatic leukodystrophy fabry disease and farber disease pharmaceutical compositions for the treatment of lipid storage diseases are also within scope of the present invention use of the compounds of the invention has also resulted in killing of a variety of cells including drug sensitive and drug resistant cells alone or in combination with other anti cancer drugs the invention thus also relates to pharmaceutical compositions for the treatment of cancerous diseases comprising as active ingredients the compounds of the invention optionally in combination with at least one other anti cancer drug still further the compounds of the invention may be used in the treatment of parasitic diseases such as malaria and leishmania pharmaceutical compositions for the treatment of such parasitic diseases are also within scope of the present invention the compounds of the invention.