Synthesis of novel N-isoquinolinyl derivatives of 6-methyluracil and their structural elucidation by modern physicochemical techniques

Abstract

6-Methyluracil is an important pyrimidine derivative that serves as a valuable building block for the synthesis of biologically active heterocyclic compounds. The incorporation of nitrogen-containing heterocyclic fragments into the 6-methyluracil molecule represents an effective approach for obtaining novel compounds with improved physicochemical and potential pharmacological properties. Among various heterocyclic systems, isoquinoline derivatives have attracted considerable scientific interest due to their structural diversity and wide range of biological activities. Therefore, the synthesis of novel N-isoquinolinyl derivatives of 6-methyluracil and the investigation of their structural characteristics are of significant importance for modern organic and medicinal chemistry. In the present study, a series of novel N-isoquinolinyl derivatives of 6-methyluracil were synthesized through nucleophilic substitution and N-alkylation reactions involving 6-methyluracil and isoquinoline-containing intermediates. The reaction conditions were optimized with respect to solvent, temperature, reaction time, and reagent ratio in order to achieve maximum yields of the target products. The synthesized compounds were isolated in good yields and purified by recrystallization. The structures of the obtained derivatives were comprehensively characterized using modern physicochemical techniques, including Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, proton and carbon nuclear 1 13magnetic resonance ( H and C NMR) spectroscopy, mass spectrometry, and elemental analysis. The spectral data confirmed the successful introduction of the isoquinoline fragment into the 6-methyluracil molecule and provided detailed information regarding the molecular structures of the synthesized compounds. FTIR spectra revealed characteristic absorption bands corresponding to N–H, C=O, C=N, and aromatic functional groups, while NMR spectroscopy confirmed the chemical environments of hydrogen and carbon atoms within the synthesized molecules. Mass spectrometric analysis further verified the molecular masses of the target compounds and supported the proposed structures. The obtained results demonstrated the successful synthesis of novel N-isoquinolinyl derivatives of 6-methyluracil and confirmed their structural integrity through complementary analytical techniques. The study provides valuable information concerning the synthesis and structural characterization of new pyrimidine–isoquinoline hybrid molecules and establishes a scientific basis for future investigations of their physicochemical, biological, and pharmacological properties.