Fig. 7.

Molecular models of (Z)-11-hexadecenoic acid (A) and superimposed hexadecanoic and 11-hexadecynoic acids (B). In B, the two structures were overlayed after minimization of the C1-C10 chain with the Chem3D Ultra 9.0 program. For the sake of clarity, because palmitic and (Z)-11-hexadecenoic acid structures are almost completely superimposable, the latter is shown out of the overlayed structures. Carbon and oxygen atoms are depicted in dark gray and red, respectively. Hydrogens are shown in light gray, except for the hydrogen atoms removed from C11, C12, C13, and C14, which are colored in green (pro-(R) in the case of enantiotopic hydrogens). White-labeled C11 and C12 correspond to hexadecanoic and (Z)-11-hexadecenoic acid; black-labeled C13 and C14 correspond to 11-hexadecynoic acid.