Nuclear magnetic resonance and molecular modeling study of exocyclic carbon–carbon double bond polarization in benzylidene barbiturates
摘要:
Benzylidene barbiturates are important materials for the synthesis of heterocyclic compounds with potential for the development of new drugs. The reactivity of benzylidene barbiturates is mainly controlled by their exocyclic carbon-carbon double bond. In this work, the exocyclic double bond polarization was estimated experimentally by NMR and correlated with the Hammett sigma values of the aromatic ring substituents and the molecular modeling calculated atomic charge difference. It is demonstrated that carbon chemical shift differences and NBO charge differences can be used to predict their reactivity. (C) 2012 Elsevier B.V. All rights reserved.