Answers are grounded in this paper and cite their sources.
The 13 C NMR spectra of methyl 2‐pyrone‐3‐, 4‐, 5‐ and 6‐carboxylates were studied and the substituent effects on the 2‐pyrone ring were compared with those of some model compounds. 1 H NMR spectra were also recorded and discussed. The long range 13 C, 1 H coupling constants were obtained, discussed and proved useful in signal assignments.
No takes yet. Share an insight, caveat, or question.
Imagawa et al. (1980) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: