Conformational analysis of carbonyl derivatives of 1,3,3-trimethyl-2-methyleneindoline

Abstract

The preferred conformations of a number of carbonyl derivatives of 1,3,3-trimethyl-2-methyleneindoline were determined by PMR spectroscopy with the use of lanthanide shift reagents. It was established that the COR group is trans-oriented relative to the heteroring nitrogen atom, and the aldehyde exists primarily in the s-trans conformation, and the ketones exist primarily in the s-cis conformation. The conclusions regarding the structures of the preferred conformations of the investigated compounds were confirmed by data from the IR spectra.