Receptor targeting compounds of mannose 6-phosphate cation-independent

A conjugate, wherein said conjugate is - a product of interest and selected from the group consisting of glycoproteins, nanoparticles and markers for medical imaging, conjugated through a linker L with - a compound having the formula ( 1) ** ** Formula wherein - the dotted line represents a bond is present or not, - X represents an analog of a phosphate group, - R is selected from the group consisting of H and OH, - a is selected the group consisting of O, S and CH2, and wherein - said compound having the formula (1) is attached to the linker through the radical a, - said linker L separates a and Y by a chain of 4 to 15 consecutive atoms when the bond represented by the dotted line is absent, X is selected from the group consisting of: saturated or a phosphonate group having the formula ** ** formula or a bis fluoro phosphonate having the formula formula ** * * or a phosphonate group having the fluoro f ormula ** ** Formula saturated or a carboxylate group having the formula ** ** Formula I a malonate group having the formula Formula ** ** - when the bond represented by the dotted line is present, X is selected from the group It is consisting of: unsaturated group or a phosphonate having the formula I ** ** formula unsaturated carboxylate group having the formula ** ** formula