118488-71-4Relevant articles and documents
EXPERIMENTAL STUDIES OF THE ANOMERIC EFFECT. PART 2 RING INVERSION AND NITROGEN INVERSION EQUILIBRIA IN CIS-DECAHYDROQUINAZOLINES
Booth, Harold,Khedhair, Khedhair A.,Al-Shirayda, Hatif A. R. Y.
, p. 1465 - 1476 (2007/10/02)
The positions of conformational equilibria due to the double ring inversion in cis-decahydroquinazoline (7-->//07-->8 1.08 kcal mol-1; -ΔG09-->10 1.10 kcal mol-1) for the conformation which would allow the lone pairs on N(1) and N(3) to lie on the hindered 'inside' face of the molecules.However, the values of 3J(CHNH) coupling constants for both cis-decahydro-3-methylquinazoline (10) and cis (4aH, 8aH) cis (2H, 8aH)-decahydro-2,3-dimethylquinazoline (14) show that the N-inversion equilibrium at N(1) prefers the conformation in which N(1)-H is 'inside' (axial), and N(1)-lone pair equatorial, thus demonstrating the ability of the anomeric effect to outweigh steric repulsions.
