The study of the formation mechanism of 1,2,3-trialkyldiaziridines by kinetic and quantum chemistry methods

Using UV spectrometry, we studied for the first time the regularities of AlkNHBr consumption in two variations of the formation of 1,2,3-trialkyldiaziridines in aqueous media: by mixing acetaldehyde and AlkNHBr in excess of AlkNH2 (method 1) and by the reaction of MeCH=NEt with EtNHBr in excess of EtNH2 (method 2). We determined the rate constants of the individual stages of the reaction. Using quantum chemistry methods (DFT/B3LYP/3-21G), we performed calculations of spatial and electronic structures of the reacting compounds, indices of local reactivity, and global electrophilicity of atoms of the individual reaction intermediates, based on which we explained the decrease in the reaction rate when using EtNHBr instead of MeNHBr in method 1. In method 2, the formation of 1,2-diethyl-3-methyldiaziridine occurs exclusively through the intermediate iminium cation.