Zaprinast

Zaprinast was an unsuccessful clinical drug candidate that was a precursor to the chemically related PDE5 inhibitors, such as sildenafil (Viagra), which successfully reached the market. It is a phosphodiesterase inhibitor,^[1] selective for the subtypes PDE5, PDE6, PDE9 and PDE11. IC₅₀ values are 0.76, 0.15, 29.0, and 12.0 μM, respectively.^[2][3]

Zaprinast

Names
IUPAC name 5-(2-Propoxyphenyl)-1H-[1,2,3]triazolo[4,5-d]pyrimidin-7(4H)-one
Other names M&B 22,948
Identifiers
CAS Number	37762-06-4 N
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL28079 Y
ChemSpider	5520 Y
ECHA InfoCard	100.048.760
IUPHAR/BPS	2919
PubChem CID	5722
UNII	GXT25D5DS0 Y
CompTox Dashboard (EPA)	DTXSID8045224
InChI InChI=1S/C13H13N5O2/c1-2-7-20-9-6-4-3-5-8(9)11-14-12-10(13(19)15-11)16-18-17-12/h3-6H,2,7H2,1H3,(H2,14,15,16,17,18,19) Y Key: REZGGXNDEMKIQB-UHFFFAOYSA-N Y
SMILES O=C1C2=C(N=NN2)NC(C3=CC=CC=C3OCCC)=N1
Properties
Chemical formula	C13H13N5O2
Molar mass	271.280 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Zaprinast inhibits the growth of asexual blood-stage malaria parasites (P. falciparum) in vitro with an ED₅₀ value of 35 μM, and inhibits PfPDE1, a P. falciparum cGMP-specific phosphodiesterase, with an IC₅₀ value of 3.8 μM.^[4]

Zaprinast has also been shown to activate the orphan G-protein coupled receptor known as GPR35, both in rats and humans,^[5] and to inhibit the mitochondrial pyruvate carrier.^[6]