PSB-10

PSB-10 is a drug which acts as a selective antagonist^[1] for the adenosine A₃ receptor (k_i value at human A₃ receptor is 0.44 nM), with high selectivity over the other three adenosine receptor subtypes (k_i values at human A₁, A_2A and A_2B receptors are 4.1, 3.3 and 30 μM). Further pharmacological experiments in a [³⁵S]GTPγS binding assay using hA₃-CHO-cells indicated that PSB-10 acts as an inverse agonist (IC₅₀ = 4 nM). It has been shown to produce antiinflammatory effects in animal studies.^[2] 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.^[3] The affinity towards adenosine A₃ subtype was measured against the radioligand PSB-11.^[4]

PSB-10

Clinical data
Other names	PSB-10
Identifiers
IUPAC name (8R)-ethyl-4-methyl-2-(2,3,5-trichlorophenyl)-4,5,7,8-tetrahydro-1H-imidazo[2,1-i]purin-5-one
CAS Number	439902-54-2 Y HCl: 591771-91-4 Y
PubChem CID	10318703
IUPHAR/BPS	5619
ChemSpider	8494167 N
UNII	2DRZ23E4F7 HCl: C2R36CZP9N Y
ChEMBL	ChEMBL1562432 N
Chemical and physical data
Formula	C16H14Cl3N5O
Molar mass	398.67 g·mol−1
3D model (JSmol)	Interactive image
SMILES Clc2cc(Cl)cc(c2Cl)C(=N3)NC1C3N(C)C(=O)N4C1=NC(C4)CC
InChI InChI=1S/C16H14Cl3N5O/c1-3-8-6-24-15(20-8)12-14(23(2)16(24)25)22-13(21-12)9-4-7(17)5-10(18)11(9)19/h4-5,8H,3,6H2,1-2H3,(H,21,22)/t8-/m1/s1 N Key:YYDHUJWLNPIBDS-MRVPVSSYSA-N N
NY (what is this?)  (verify)