Tetrazoles and Pyrimidines: Preparation Methods, Spectroscopic Characterization, and Biological Importance

Tetrazoles and pyrimidines are nitrogen-rich heterocycles with broad importance in synthetic and medicinal chemistry. This study presents the preparation and spectroscopic characterization of representative tetrazole and pyrimidine derivatives and places the obtained compounds within the wider context of biologically active heterocycles. Pyrimidine derivatives (AD8–AD12) were synthesized by cyclocondensation of substituted chalcones with cyanoguanidine in ethanol in the presence of glacial acetic acid, whereas tetrazole derivatives were prepared through azide–nitrile or azide-assisted cyclization under heating. The products were isolated by precipitation, filtration, washing, and recrystallization. Their physical properties were evaluated from color, melting point, molecular formula, and isolated yield, while structural assignments were supported by Fourier-transform infrared spectroscopy and, for selected compounds, by ¹H and ¹³C nuclear magnetic resonance data. The pyrimidine series gave isolated yields of 44–65%, and the tetrazole series gave yields of 55–70%. Diagnostic FTIR bands included N–H, aromatic C–H, C=N/C=C, N=N, C–N, and N–N vibrations, together with substituent-specific absorptions. The results support successful heterocycle formation and illustrate the value of both ring systems as adaptable scaffolds for further pharmacological evaluation. No direct antimicrobial assay was reported; therefore, biological relevance is discussed on the basis of established literature rather than inferred from the present synthetic data.