Hydroacridines: Part 33. An experimental and DFT study of the 13C NMR chemical shifts of the nitrosamines derived from the six stereoisomers of tetradecahydroacridine.

Autor: Potmischil, Francisc, Hillebrand, Mihaela, Kalchhauser, Hermann
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Zdroj: Magnetic Resonance in Chemistry; Mar2020, Vol. 58 Issue 3, p249-259, 11p
Abstrakt: The paper presents the experimental and DFT‐calculated values of the 13C NMR chemical shifts of the six stereoisomers of tetradecahydroacridine and of the corresponding nitrosamines. Performing the DFT calculations using several combinations of functional and basis sets, it was found that the best experimental‐calculated agreement was obtained for OPBE/6–311++G (dp) method. Considering the effect of N‐nitrosation upon the 13C NMR chemical shifts of the C‐α carbons of secondary amines, it was found that if following nitrosation both C‐α carbons are shifted upfield or both are shifted downfield, then the resulted nitrosamine will have a sterically strained ─N═O group. If, however, one of the C‐α is shifted upfield and the other is shifted downfield, then the ─N═O group will be strain‐free or weakly strained. Our calculations predict strain energies of about 10–15 kcal mol−1 in the first case and ≈0–6 kcal mol−1 in the latter. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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