| Abstract: | The mechanism of one‐carbon unit transfer between 1‐methyl‐5‐amino‐4‐carboxamide imidazole (M‐AICA) and N1‐methyl‐N1‐acryloyl‐formamide (the model molecule of 10‐f‐H4F) is investigated by the Hartree–Fock and DFT methods, respectively, at the 6‐31G* basis level. There are two different channels for the proton transfer, resulting in two reaction pathways with different properties. The results indicate that both channels can complete the reaction, but path a is slightly favored due to its lower active energy barrier. Furthermore, the influence of 4‐carboxamindde in M‐AICA is also discussed. This group can stabilize the reactant and intermediates, and reduce the active energy barrier through the intermolecular hydrogen bond. The intermolecular hydrogen bond results in an enlarged conjugation system and makes the transition states more stable. Our results are in agreement with experiments. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 |
