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The carbon-13 nuclear magnetic resonance spectra of tetronate and 2-pyrone derivatives

The 13C n.m.r. spectra of a variety of tetronic acids, methyl tetronates, 4-methoxy-2-pyrones, and 4-methoxy-5,6-dihydro-2-pyrones are reported. Signals have been assigned on the basis of a variety of techniques including gated decoupling, selective proton decoupling, and hydrogen–deuterium exchange experiments. The results should be of use for structural assignments and for biosynthetic studies of natural products.