A3 adenosine receptors (ARs) belong to the superfamily A of G-protein coupled receptors. When activated, A3 AR could inactivate adenylyl cyclase or stimulate phospholipase C or D.1 Antagonists for the A3 AR are promising agents for the treatment of asthma, inflammation and glaucoma.1 In addition detectable hA3 AR antagonists are useful in ligand discovery and receptor localization imaging. A simple strategy in order to obtain such antagonists is to link fluorophore, or other detectable groups, to a conjugable hA3 AR antagonist.2 Herein, we report the exploration of new possible aminoacid spacers at the 5 position of the well-known pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine (PTP) scaffold as site of linkage for functionalizing moieties, that can be useful in the study of the physio-pathological role of A3 AR.
[1] S.L. Cheong, S. Federico, G. Venkatesan, A.L. Mandel, Y.M. Shao, S. Moro, G. Spalluto and G. Pastorin Med. Res. Rev., 2013, 33, 235-335.
[2] 18. E. Kozma, M.P.S. Jayasekara, L. Squarcialupi, S. Paoletta, S. Moro, S. Federico, G. Spalluto and K.A. Jacobson Bioorg. Med. Chem. Lett., 2013, 23, 26-36.
