Theoretical study of the hydrolysis of a model carbapenem: 1-Aza-bicyclo[3,2,1]hept-2-ent-7-one

The hydrolysis of a model carbapenem, 1-aza-bicyclo[3,2,1]hept-2-ent-7-one, has been investigated using density functional theory method at both B3LYP/6-31G(d) and B3LYP/6-311+G(d,p) level. The geometries, energies and frequencies of all the stationary points were calculated in detail. Different possible reaction mechanisms have been proposed. The outcomes show that both in the non-assisted mechanism and the water-assisted mechanism, the concerted pathway a is preferred. However, the energy barrier of water-assisted mechanism is much lower than that of non-assisted mechanism.