5382-26-3Relevant articles and documents
RING INVERSION EQUILIBRIA IN 4-CHLORO-, 4-BROMO-, AND 4-METHOXY-1-ALKYLPIPERIDINES IN A NON-POLAR SOLVENT
Bailey, Judith M.,Booth, Harold,Al-Shirayda, Hatif A.R.Y.,Trimble, Mary L.
, p. 737 - 744 (2007/10/02)
The position of ring inversion equilibrium (axial Requuatorial R) in 4-R-N-alkylpiperidines (R = Cl, Br, or OMe), dissolved in CFCl3-CDCl3, has been determined by (13)C n.m.r. spectroscopy at low temperatures.In all three series, change of NH to NMe produces a marked increase in the proportion of conformation with axial R.When R is OMe, further alterations in the N-substituent from Me to Et, Pri, and CH2CF3 do not affect the equilibrium significantly, but the signifficant changes observed when R is halogen can be related to the inductive effect of the N-substituent. (13)C Chemical shifts, proportions of conformations, and conformational free energy differences are recorded for all systems studied.