C. F. Bernasconi, D. Ohlberg, M. W. Stronach
Apr 1, 1991
Citations
0
Influential Citations
10
Citations
Journal
Journal of Organic Chemistry
Abstract
Rates of reversible deprotonation of 3,5-heptanedione (6b), 2,6-dimethyl-3,5-heptanedione (6c), and dibenzoylmethane (6d) by several primary aliphatic amines, by piperidine and morpholine, and by hydroxide ion (6b and 6d only) have been measured in 50% Me 2 SO-50% water (v/v) at 20 o C. Apparent pK a 's as well as the pK a values of the keto and the enol forms, and the enolization equilibrium constantes (K T ) were also determined. The pK a and K T values show the same trends observed previously in water. The intrinsic rate constants for the reactions of 6b and 6c with a given family of amines (primary aliphatic or secondary alicyclic) and the same and also equal to those for the reaction of acetylacetone (6a) with the same amines determined previously. These results indicate that steric effects play an insignificant role in the reactions of 6a, 6b, and 6c