Synthesis and RP HPLC studies of biologically active semicarbazides and their cyclic analogues 1,2,4-triazol-3-ones

ABSTRACT: The retention behaviour of semicarbazides and their cyclic analogues 1,2,4-triazol-3-ones, has been investigated by RP-8, RP-18 and IAM HPLC. The structures of new derivatives were proved by elemental analyses, IR, (1)H NMR and (13)C NMR spectroscopy. The compounds showed regular retention behaviour in three chromatographic systems; their log k values decreased linearly with the increasing concentration of an organic modifier in the mobile phase. The ratio of the intercept (log k (w)) to the slope of compounds is constant and the same for both groups of compounds on C18 and IAM stationary phases. Differences between log k (w) values from the octadecyl stationary phase of corresponding cyclic and linear derivatives are constant, and they are related to the mechanism of synthesis of 1,2,4-triazol-3-ones from linear substrate semicarbazides, which was confirmed by modelling studies. Good correlations between log k (w) parameters obtained by RP-8 or RP-18 and determined by the computational approach log P were found. GRAPHICAL ABSTRACT: [Image: see text]