Identification of Intermediates and Products of 2,4,6-Trimethyl-1,3,5-Hexahydrotriazine Trihydrate and Glyoxal Reaction in an Aqueous Solution by NMR Spectroscopy

The reaction of acetaldehyde, glyoxal, and ammonia to yield 2-methylimidazole: thermodynamic and kinetic analyses of the mechanism

“…Comparison of the experimental results with theoretical data showed that the hypothesized amine intermediate compounds, which had low positions on the PES, contained the experimentally detected fragments (–CH–CH 3 ; –NH 2 ; –CO), 30 which was consistent with the opportunity for their detection because of their greater stability and longer lifetime. A thermodynamic analysis of the positions of the proposed structures of the 2MI formation mechanism showed that the imine intermediates widely discussed in the literature were characterized by high positions on the PES in terms of the Gibbs free energy, which indicated their absence or short lifetimes in the reaction mixture.…”

“…Our previous experimental studies of the THT interaction with glyoxal in aqueous solution by in situ NMR 30 showed that, along with the signals of reagents and reaction products, the system contained those of structures including –CH and –CH 3 fragments despite the fact that these fragments were bonded, as well as amino and carbonyl groups. Comparison of the experimental results with the theoretical data shows that the proposed intermediate compounds X, V, Y, Z, W, U, 2, 3 and 4 that contain the experimentally detected fragments (–CH–CH 3 ; –NH 2 ; –CO) have low positions on the PES (−4.7; −1.9; −10.1; −8.0; −5.3; −8.9; −3.1; −0.5; −2.3 kcal mol −1 , respectively), which is consistent with the opportunity for their detection due to their greater stability and longer lifetime.…”

Reaction Pathway and Kinetic Study of 4,5-Dihydroxyimidazolidine-2-thione Synthesis by HPLC and NMR

“…The kinetics of the thiourea interaction with glyoxal has not been investigated, unlike substituted thiourea with substituted dialdehydes. 10 In the references, 11,12 a pathway for aldehyde reaction with nitrogen-containing organic compounds was studied by DFT and NMR. In the reference, 13 the conditions of HPLC analysis of DHIT were developed.…”