210362-85-9Relevant academic research and scientific papers
Synthesis, structure, and stereodynamics of an N,N-chiral 'proton sponge'
Charmant, Jonathan P. H.,Lloyd-Jones, Guy C.,Peakman, Torren M.,Woodward, Robert L.
, p. 2501 - 2510 (2007/10/03)
1,8-Bis(N-benzyl-N-methylamino)naphthalene (2) and its hydrogen iodide salt [2H]+[I]- were synthesised from 1,8-diaminonaphthalene. The thermodynamic diastereomer ratios of (2) and [2H]+ in [D7]DMF are 73.4:26.6 and 89.7:10.3 respectively at 293 K. The solid state structures of the major dl-(R(N)R(N)/S(N)S(N)) diastereomers were determined by single crystal X-ray diffraction. The minor diastereomers were shown to be the meso-(R(N)S(N)) forms by performing 1H-NMR NOE studies on isotopically desymmetrized 1-(N- benzyl-N-[13C]-methylamino)-8-(N'-benzyl-N'-methylamino)naphthalene [13C]-2 and the salt [13C]-[2H]+. In [D7]DMF at 298 K, the meso form of the free base 2 is 0.6 (± 0.07) kcal · mol-1 less stable than the d1 form (ΔH°= -0.64 (±0.03) kcal · mol-1; ΔS°= -0.18 (±0.13) cal · K- 1mol-1) and the activation barriers for interconversion are ca. 14,2 (±0.4) and 14,8 (±0.4) kcal · mol-1 respectively. The effect of solvent polarity on the entropy and enthalpy change on approach to the transition state was studied. An approximate correlation with the solvent dielectric constant was found for both ΔH((+)) and ΔS((+)) and this may be ascribed to the development of a net dipole in the transition state due to substantially different hybridisation and geometry at the two nitrogen centres.
Synthesis of a protonated C2-symmetric N,N-chiral 'proton sponge'
Charmant, Jonathan P. H.,Lloyd-Jones, Guy C.,Peakman, Torren M.,Woodward, Robert L.
, p. 4733 - 4736 (2007/10/03)
The hydrogen iodide salt of 1,8-bis-(N-benzyl-N-methylamino)naphthalene was synthesised as an 89 / 11 ratio of diastereomers in good yield. The structure of the major (±)-(R(N)R(N)/S(N)S(N)) diastereomer was determined by single crystal X-ray diffraction. The minor diastereomer is shown to be the meso-(R(N)S(N)) form by performing 1H NMR n.O.e studies on isotopically desymmetrized 1-(N-benzyl-N-[13C]-methylamino)-8-(N'-benzyl-N'- methylamino)naphthalene (HI salt). The half-life of interconversion of meso and dl forms is less than 2 minutes in CD2Cl2 at ambient temperature.
