Synthesis, Crystal Structure, Molecular Docking, and Molecular Dynamics Simulations of 2,5-Substituted Pyrazolo[4′,3′:5,6]Pyrano[2,3-d]Pyrimidines as Selective Ligands for Adenosine A1 and A2A Receptors

Abstract

This study focuses on the design of selective ligands targeting A₁ and A_2A adenosine receptor subtypes, which are part of the G protein-coupled receptor (GPCR) family. A series of novel pyrazolopyranopyrimidine derivatives 7–12 were synthesized from pyrano[2,3-c]pyrazole-5-carbonitrile 1. The structures of the synthesized compounds were confirmed by NMR spectroscopy, and X-ray crystallography was used to validate Compounds 2 and 6. Molecular docking studies were conducted to evaluate their binding affinities for the human adenosine A₁ and A_2A receptors, with Compounds 2 and 6 showing promising interactions. Additionally, density functional theory calculations were employed to optimize molecular geometries, investigate electronic properties, and support the spectral and stability analysis of these compounds. Molecular dynamics (MD) simulations over 100 ns were performed on the receptor–ligand complexes, particularly for Compound 2, to assess their stability and dynamic behavior in a biological environment. These findings highlight Compound 2 as a potential lead for further development as a selective adenosine receptor ligand. The combined synthetic and computational approach offers valuable insights for future drug discovery efforts targeting GPCRs.