¹³C NMR spectra of benzofuroxan and related compounds

Abstract

Abstract The 13 C n.m.r. spectrum of benzofuroxan at −15°C is assigned on the basis of selective decoupling experiments and by comparison with the 13 C chemical shifts of model compounds. The 13 C spectra were also measured in trifluoroacetic acid as a solvent. From the temperature dependence of the 13 C spectrum of benzofuroxan in CDCl 3 , a barrier of 14·0 ± 0·2 kcal mol −1 is obtained for the degenerate tautomerism in this compound.