UDP made a highly promising stable, potent, and selective P2Y6-receptor agonist upon introduction of a boranophosphate moiety

P2Y₆ nucleotide receptor (P2Y₆-R) plays important physiological roles, such as insulin secretion and reduction of intraocular pressure. However, this receptor is still lacking potent and selective agonists to be used as potential drugs. Here, we synthesized uracil nucleotides and dinucleotides, substituted at the C5 and/or P_α position with methoxy and/or borano groups, 18-22. Compound 18A, R_p isomer of 5-OMe-UDP(α-B), is the most potent and P2Y₆-R selective agonist currently known (EC₅₀ 0.008 μM) being 19-fold more potent than UDP and showing no activity at uridine nucleotide receptors, P2Y₂- and P2Y₄-R. Analogue 18A was highly chemically stable under conditions mimicking gastric juice acidity (t_1/2 = 16.9 h). It was more stable to hydrolysis by nucleotide pyrophosphatases (NPP1,3) than UDP (15% and 28% hydrolysis by NPP1 and NPP3, respectively, vs 50% and 51% hydrolysis of UDP) and metabolically stable in blood serum (t_1/2 = 17 vs 2.4, 11.9, and 21 h for UDP, 5-OMe-UDP, and UDP(α-B), respectively). This newly discovered highly potent and physiologically stable P2Y₆-R agonist may be of future therapeutic potential.