Synthesis of photolabile mono- and di-valent α-d-mannoside-6-phosphates as chemically modifying probes for mannose-6-phosphate-receptors

Two photoaffinity probes, disodium 3′-azibutyl α-d-mannopyranoside-6-phosphate and tetrasodium 2-azi-1,10-bis(α-d-mannopyranosyloxy-6-phosphate)decane were synthesized for the regioselective chemical modification of mannose-6-phosphate receptors. Disodium 3′-azibutyl α-d-mannopyranoside-6-phosphate was obtained by chemical α-mannosylation of 3-azibutanol and subsequent 6-phosphorylation of the mannosyl residue. The corresponding divalent ligand, mimicking a high mannose oligosaccharide with two mannose-6-phosphate end groups, was obtained by the same procedure but with 2-azi-1,10-decanediol as the aglyconic alcohol. In preliminary experiments, both photolabile ligands had affinity to cation-independent mannose-6-phosphate receptors from bovine testes.