Investigation of Redox Mechanisms of Biologically Active Hydantoin Derivatives by Different Voltammetric Methods

The electrochemical behavior of four biologically active cycloalkane espirohydantoins with 5-, 6-, 7-, and 8-membered rings: 1,3-diazaspiro[4.4] nonane-2,4-dione (CSH(5)); 1,3-diazaspiro[4.5]decane-2,4-dione (CSH(6)); 1,3-diazaspiro[4.6]undecane-2,4-dione (CSH(7)); and 1,3-diazaspiro[4.7]dodecane-2,4-dione (CSH(8)) has been investigated at the pH range 1.81-12 by modern electrochemical techniques as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The electrochemical studies were carried out on a hanging mercury drop electrode (HMDE) at room temperature. CSH(5) and CSH(6) at pH 5.50 and 7.63 and CSH(7) at pH 5.50 showed a single quasireversible peaks. For CSH(7) at pH 7.63 and CSH(8) at two pH values the irreversible nature of the electrode process was proved. The effect of scan rate, pH and concentration on peak current and peak potential was investigated. Physical parameters like diffusion coefficient and heterogeneous electron transfer rate constant were determined from scan rate and concentration effects. The number of proton transfer in the electrochemical reaction was determined from the peak potential shift as a function of pH and a mechanism of cycloalkanespiro-5-hydantoins derivatives on the basis of CV, SWV and DPV results was proposed. The proposed mechanisms of the cited cycloalkane spiro-5-hydantoins could be essential in regard to the hidden pathways by which such compounds exert their biochemical actions.