Synthesis of Size-Expanded Nucleobase Analogues for Artificial Base-Pairing Using a Ligand-Free, Microwave-Assisted Copper(I)-Catalyzed Reaction

Abstract: Quinazolines is an important class of natural products. Size-expanded isocytosine analogues or 2-aminoquinazolinones have found significance as pharmaceutically active compounds, for the expansion of genetic alphabets and as biomolecular probes. With an aim for further biomolecular applications, a library of functionalized isocytosine analogues have been synthesized in a one-pot, microwave-directed reaction. Syntheses were carried out using simple reactants such as ortho-halo aromatic carboxylic acids and guanidine hydrochloride, in absence of any additional ligand. The usefulness of the methodology could be justified by the diversity of the compounds synthesized, containing functional groups, natural nucleobases, fluorophores or peptide bonds.