Reactivity model for the Menschutkin reaction. Methylation of alkyl-substituted and heterosubstituted pyridines was written by Schug, John C.;Viers, Jimmy W.;Seeman, Jeffrey I.. And the article was included in Journal of Organic Chemistry in 1983.Reference of 644-98-4 This article mentions the following:
The relative activation energies for the methylation of pyridine and 37 alkyl- and 6 heterosubstituted pyridines were calculated using semiempirical all-valence electron (MINDO/3) SCF procedures. The alkylation rates covered >5 orders of magnitude. A reactivity model was constructed by placing a Me+ moiety 1.88 Å from the pyridine N and completely optimizing the Me+-substrate supermol. A transition-state (TS) model was determined by considering the dequaternization of the N-methylpyridinium cation. The energy difference between the TS model and the completely optimized ground-state mol. for the 44 compounds resulted in a good correlation with the logarithms of the methylation rate constants Implications of this work to nonadditive steric and electronic effects are considered. The model is used to evaluate changes in the TS position in these methylations. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Reference of 644-98-4).
2-Isopropylpyridine (cas: 644-98-4) belongs to pyridine derivatives. Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.The molecular electric dipole moment is 2.2 debyes. The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase. Many analogues of pyridine are known where N is replaced by other heteroatoms . Substitution of one C–H in pyridine with a second N gives rise to the diazine heterocycles (C4H4N2), with the names pyridazine, pyrimidine, and pyrazine.Reference of 644-98-4