Theoretical study of pyrazole elimination of N‐alkyl pyrazoles

The gas‐phase pyrazole elimination of N‐alkyl pyrazoles has been studied using MNDO semi‐empirical molecular orbital (MO) theory with complete geometry optimization of all stationary points. We found that the activation energies (Ea) of the concerted processes are around 80 kcal/mol, 25 Kcal/mol higher than experimental values. But the differences in Ea between compounds with different substituents are in good agreement with the experimental ones.