(A) Structures of, Δ1,7-DA (dafa#1), Δ7-DA (dafa#2), 3α-OH-Δ7-DA (dafa#3), Δ4-DA (dafa#4), Δ0-DA (dafa#5), and 3β-OH-Δ7-DA (dafa#6). See Experimental Procedures for compound nomenclature.
(B) NMR-spectroscopic determination of the relative configuration at C-25 in natural Δ7-DA. C-18 singlet region of 1H NMR spectra (600 MHz, pyridine-d5) of natural Δ7-DA and mixtures with synthetic (25R)-Δ7-DA and (25S)-Δ7-DA.
(C) NMR-spectroscopic determination of the relative configuration at C-25 in natural Δ1,7-DA. C-18 singlet region of 1H NMR spectra (600 MHz, pyridine-d5) of natural Δ1,7-DA and mixtures with synthetic (25R)-Δ1,7-DA and synthetic (25S)-Δ1,7-DA.