Synthesis and photophysical properties of 2-azolyl-6-piperidinylpurines

[Figure not available: see fulltext.] A synthesis of novel fluorescent 2-azolyl-6-piperidinylpurine derivatives was designed. Azolyl substituent at purine C-2 atom was introduced via nucleophilic aromatic substitution or in the case of tetrazolyl and 1,2,3-triazolyl substituents via a ring formation on a preinstalled amine or azide moiety, respectively. The obtained purine intermediates were functionalized at N-9 position using Mitsunobu reaction conditions to achieve amorphous compounds, which form thin-layer films of good quality. The synthesized push-pull systems exhibited fluorescence with emission in range of 360–400 nm and quantum yields up to 66% in CH₂Cl₂ solution and up to 45% in the thin-layer film.