1457967-20-2Relevant academic research and scientific papers
Structure-activity relationships in Toll-like receptor 7 agonistic 1H-imidazo[4,5-c]pyridines
Yoo, Euna,Crall, Breanna M.,Balakrishna, Rajalakshmi,Malladi, Subbalakshmi S.,Fox, Lauren M.,Hermanson, Alec R.,David, Sunil A.
, p. 6526 - 6545 (2013/09/24)
Engagement of TLR7 in plasmacytoid dendritic cells leads to the induction of IFN-α/β which plays essential functions in the control of adaptive immunity. We had previously examined structure-activity relationships (SAR) in TLR7/8-agonistic imidazoquinolines with a focus on substituents at the N 1, C2, N3 and N4 positions, and we now report SAR on 1H-imidazo[4,5-c]pyridines. 1-Benzyl-2-butyl-1H-imidazo[4,5-c] pyridin-4-amine was found to be a pure TLR7-agonist with negligible activity on TLR8. Increase in potency was observed in N6-substituted analogues, especially in those compounds with electron-rich substituents. Direct aryl-aryl connections at C6 abrogated activity, but TLR7 agonism was reinstated in 6-benzyl and 6-phenethyl analogues. Consistent with the pure TLR7-agonistic behavior, prominent IFN-α induction in human PBMCs was observed with minimal proinflammatory cytokine induction. A benzologue of imidazoquinoline was also synthesized which showed substantial improvements in potency over the parent imidazopyridine. Distinct differences in N6-substituted analogues were observed with respect to IFN-α induction in human PBMCs on the one hand, and CD69 upregulation in lymphocytic subsets, on the other.
