C. F. Bernasconi, M. W. Stronach
Mar 1, 1991
Citations
0
Influential Citations
23
Citations
Journal
Journal of Organic Chemistry
Abstract
The kinetics of the reaction of benzylidenemalonodialdehyde with piperidine, morpholine, n-butylamine, 2-methoxyethylamine, glycinamide, glycine ethyl ester, cyanomethylamine, and semicarbazide have been determined in 50% aqueous Me 2 SO at 20 o C. The reaction leads to a zwitterionic adduct, PhCH(RR'NH + )C(CHO) 2 − (T A ± ), that is in fast acid-base equilibrium with the anionic adduct, PhCH(RR'N)C(CHO) 2 − (T A − ). With strongly basic amines at high pH there is also attack of the amine on one of the carbonyl groups, which acts as a rapid preequilibrium. Rate constants for the formation of T A ± (κ 1 ) and its reverse (κ −1 ), as well as equilibrium constants (K 1 =κ 1 /κ −1 ) and the pK a of T A ± , were determined for all the amines. Intrinsic rate constants (κ 0 =κ 1 =κ −1 ) and the pK a of T A ± , were determined for all the amines. Intrinsic rate constants (κ 0 =κ 1 =κ −1 when K 1 =1) were calculated