Carbon-13 Nuclear Magnetic Resonance Study of meso-Hexestrol and Its Derivatives

The carbon-13 nuclear magnetic resonance chemical shift assignments for meso-hexestrol (la), made on the basis of two-dimensional ¹³C-¹H chemical shift correlation, long-range selective 1H decoupling experiment, and a reported two-dimensional Fourier-transform experiment for long-range proton-carbon-13 spin coupling constants, are reported. For measurement of carbon-proton coupling constants of meso-hexestrol derivatives (lb—e, 2a—d, 3a—c, and 4), the coupling information was detected by using a gated decoupling facility which permitted retention of the nuclear Overhauser enhancement and a long-range selective ¹H decoupling experiment. The results showed that the aromatic carbon resonances are influenced by the structure (no double bond, or one or two double bond(s)) of the hexane framework in the central portion.