Unique charge-separated pyridinium-barbituric acid zwitterions.
A synthetic procedure for the preparation of the unusual charge-separated pyridinium barbiturate zwitterion 2 from 1,3-dimethylbarbituric acid and 2-pyridinecarbaldehyde in methanol was developed. The structure of the compound was confirmed with X-ray analysis to demonstrate the strong charge separation throughout the molecule. One would expect that this charge separation would increase its reactivity; however, contrary to this expectation, the compound is very stable in acidic media, and in the presence of a base, decarbonylation occurs on one barbituric acid while the zwitterionic moiety of the molecule stays intact.
Jursic
Branko S
BS
Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, USA. bsjcm@uno.edu
Neumann
Donna M
DM
Moore
Zakhia
Z
Stevens
Edwin D
ED