Hindered Internal Rotation about a C-N Bond in Some Trisubstituted 1,3,5-Triazines

We have studied the temperature dependence of the ¹H NMR spectra of some 2,4,6-trisubstituted 1,3,5-triazines having an NHAlk or NAlk₂ group or groups at the position 2 or 2 and 4 of the heterocycle. We have shown that rotation of these groups about the C-N bond is hindered. We have calculated the free energies of activation for the rotation processes. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1236–1239, August, 2005.