Interpretation of substituent-induced 13C NMR chemical shifts of oxindoles

Abstract

Based on the ¹³C NMR chemical shifts of more than 300 oxindole derivatives, substituent-induced chemical shifts have been calculated for this family of compounds. These substituent effects have been compared to those of monosubstituted benzenes and the correlation with the Hammett σ values and dual substituent parameters has also been tested. By means of these validated substituent effects, the ¹³C NMR chemical shifts of the oxindole skeleton containing various substituents can be accurately predicted.