Influence of calculation level and effect of methylation on axial/equatorial equilibria in piperidines

@article{Carballeira1998InfluenceOC,
  title={Influence of calculation level and effect of methylation on axial/equatorial equilibria in piperidines},
  author={Luis Carballeira and Ignacio P{\'e}rez-Juste},
  journal={Journal of Computational Chemistry},
  year={1998},
  volume={19}
}
A detailed conformational analysis was performed on the chair forms of piperidine, N‐methylpiperidine, and some methylated derivatives using Hartree–Fock (HF) and MP2 ab initio methods with several basis sets (from 3–21G to 6–311++G**), and the most widely used semiempirical approaches (MNDO, AM1, and PM3). It was found that the use of polarized basis sets at the HF level is adequate enough for the prediction of conformational preferences in the axial/equatorial equilibrium of the N‐R group in… 

N-Methyl stereochemistry in tropinone: the conformational flexibility of the tropane motif.

The intrinsic conformational and structural properties of the tropinone azabicycle have been investigated in a supersonic jet expansion using rotational spectroscopy. The spectrum revealed the

The conformational landscape of nicotinoids: solving the conformational disparity of anabasine.

TLDR
The conformational landscape of the alkaloid anabasine (neonicotine) has been investigated by using rotational spectroscopy and ab initio calculations, determining accurate rotational and nuclear quadrupole coupling parameters.

N-Methyl inversion and structure of six-membered heterocyclic rings: rotational spectrum of 1-methyl-4-piperidone.

TLDR
The conformational and structural properties of the six-membered heterocyclic ring of 1-methyl-4-piperidone have been observed in a jet-cooled supersonic expansion using Fourier transform microwave spectroscopy (FT-MW) to determine substitution and effective structures for the equatorial conformer.

Quantum chemical study of the equatorial/axial exchange of different substituents in nitrogen and phosphorous-containing 6-membered rings: Role of charge transfer interactions

Understanding the nature of equatorial/axial conversion in six-membered rings is important because of involvement of these motifs in some biological systems. In this work we have studied the

Conformational Analysis of Saturated Heterocyclic Six-Membered Rings

Publisher Summary Saturated six-membered heterocyclic rings can be found in natural products, drugs, and polymers. The methodologies for studying the conformers at equilibrium and their rates of