1,3,5-Triazines quantum-chemical calculations

According to quantum-chemical calculations, the second pathway is preferable. Thus, 2,4,6-tris-trifluoromethyl-l,3,5-triazine 36 reacts readily with active electron-rich dienophile, 3-aminopyrrole 37, generated in situ, yielding 2,4-bis-(trifluoromethyl)-5H-pyrrolo[3,2-(f]pyrimidine 38. The electron-withdrawing trifluoromethyl groups facilitate the reaction which proceeds at room temperature giving an 85% yield of 38 (13JOC8614). 

The Henry s law constants (77) for triazine-derived herbicides have been calculated using quantum-chemical solvation models, SM2, SMS, PCM-DFT, and CPCM-DFT, and their performances have been discussed. The results showed considerable differences in performance among the different levels of theory. The differences were discussed in terms of the different contributions, electrostatic and nonelectrostatic, to Gibbs free energy of solvation <2003JCI1226>. 

The stability to the photochemieal rearrangements with the triazine eyele expansion in the triplet nitreno-l,3,5-triazines inereased with an inerease in the D-parameter of splitting in zero field found from the ESR spectra, which, in its turn, correlated with the spin density on the nitrene center calculated quantum-chemically [87], Triplet nitrenes with D/hc > 1.40 cm and pa > 1.77 (UB3LYP/6-31G ) were photochemically very stable and did not rearrange into carbodiimides. 

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