kf-26777 kf-26777 kf-26777 is a drug which acts as a potent and selective antagonist for the adenosine a3 receptor, with sub-nanomolar affinity (a3 ki=0.2nm) and high selectivity over the other three adenosine receptor subtypes. simple xanthine derivatives such as caffeine and dpcpx have generally low affinity for the a3 subtype and must be extended by expanding the ring system and adding an aromatic group to give high a3 affinity and selectivity. kf-26777clinical dataother nameskf-26777identifiers iupac name (2-(4-bromophenyl)-7,8-dihydro-4-propyl-1h-imidazopurin-5(4h)-one cas number206129-88-6 ypubchem cid9820916chemspider7996665uniin33070gi64chemblchembl2181965chemical and physical dataformulac16h18brn5omolar mass376.258 g·mol−13d model (jsmol)interactive image smiles cccn(c2=o)c1n=c(c(cc3)ccc3br)nc1c=4n2ccn=4 inchi inchi=1s/c16h16brn5o/c1-2-8-21-15-12(14-18-7-9-22(14)16(21)23)19-13(20-15)10-3-5-11(17)6-4-10/h3-6h,2,7-9h2,1h3,(h,19,20)key:gygnzjdwthecqt-uhfffaoysa-n (verify)