108
WERNER BERGMANN
H,C.
,CH 3
S CH 8
H S C.
G
24-/8 -series
H,C
24-a-series
HX
H
24-0-series
H.C
K
24-a-series
„CH ft
.CH,
H,C
H.C
CH Q
L
24-ß-series
H,C
H.C
M
24-0 -series
20-iso pr 20-/3-series
Diunsaturated side chains
spectroscopy was in the field of sterols. More than thirty years ago it
served to discover that the precursors of vitamin D in sterol mixtures
are compounds with conjugated double bonds. It is still the best method
for the facile detection of such groups in sterols. Since they are comparatively rare, however, the usefulness of ultraviolet absorption spectra
in the field of natural sterols is rather limited. In the meantime the
infrared spectra of sterols have become an indispensable tool in the identification of sterols and the elucidation of their structures. Prior to the
introduction of infrared spectroscopy, for example, a terminal methylene