The synthesis of five l-glycero-d-manno-heptose monophosphates

From suitably protected benzyl α-d-mannopyranosides, five benzyl l-glycero-α-d-manno-heptopyranosides were synthesized by chain-elongation at C-6. By regiospecific protection-deprotection procedures five O-benzylated heptosides having ‘isolated’ free OH groups at C-2, C-3, C-4, C-6, or C-7 were obtained. These substrates were phosphorylated and the products were converted into free monophosphates or monophosphate cyclohexylammonium salts (1–5) which were characterized by 1H, 13C, and 31P NMR spectra and high-performance anion-exchange chromatography.