d--β-d-heptose Phosphate 7--Modifications.

Pathogen-associated molecular patterns activate the immune system via pattern recognition receptors. Recently, newly discovered pathogen-associated molecular patterns, d--β-d-heptose phosphate and d--β-d-heptose 1,7-biphosphate, were shown to induce a TRAF-interacting protein with a forkhead-associated domain-dependent immune response in human embryonic kidney cells and colonic epithelial cells. Concurrently, ADP-heptose was shown to bind α-kinase 1 and activate TIFA via phosphorylation leading to an immune cascade to ultimately activate NF-κB. These pathogen-associated molecular patterns have raised interest in the pharmaceutical industry for their potential use as immunomodulators. However, little is understood about the host cell uptake of d--β-d-heptose phosphate, d--β-d-heptose 1,7-biphosphate, and ADP-heptose in vivo and derivatives of these molecules are needed to interrogate this. In this regard, herein we describe 7--modifications of d--β-d-heptose phosphate to produce molecular probes toward the development of a useful toolbox for biologists. A convergent strategy that involves introduction of a substituent at -7 before alkene oxidation was investigated and proved successful in the generation of a range of molecular probes.