NMR spectral studies of dimedone-aldehyde adducts Part 1. 1H and 13C NMR spectral studies of dimedone

Abstract

A detailed study of the 270 MHz 1H and 67 MHz 13C NMR spectra of dimedone is reported. J CH coupling constants for the keto and enol forms are presented. In CDCl 3 solution, the C-4 and C-6 carbons of the bulk polymeric enol tautomer are equivalent, with an averaged coupling to C-2, whilst they appear to be magnetically different in the individual monomeric enol and enolic forms. In dry DMSO- d 6 solution, dimedone exists almost exclusively as the enol tautomer, the C-1/C-3 and C-4/C-6 carbons being magnetically different.