High Resolution ¹³C Spectrum and Long-Range ¹³C,H Couplings in 2-Pyrone

Abstract

The natural abundance 13C n.m.r. spectrum of 2-pyrone has been analyzed by the 13C–{1H} SPI technique. The magnitudes and signs of all long-range 13C,H couplings have been obtained and are compared with those of related compounds.

Carbon‐13 nuclear magnetic resonance spectra of methyl 2‐pyronecarboxylates

“…In pyridine," 2J(C-2, H-3) and 2J(C-3, H-2), related to a C or a H atom adjacent to the hetero atom, are of the order of 8-9Hz. In furan," 'J(C-2, H-3) and 'J(C-3, H-2) are larger than 10Hz (11)(12)(13)(14). In the 2-pyrones, contrary to furan, none of the ' 5 couplings associated with C-2, C-6 or H-6 exceeds 9 Hz, as in 4-pyr0nes.I~…”