The 5
![]()
SRC="/image
s/gifchar
s/alpha.gif" BORDER=0>-hydroperoxide
s of
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-
sito
sterol, campe
sterol,
stigma
sterol, and bra
ssica
sterol were obtainedby photooxidation of the re
spective
sterol
s in pyridine in the pre
sence of hematoporphyrine a
ssen
sitizer. The reduction of the hydroperoxide
s give
s the corre
sponding 5
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>-hydroxy derivative
s.The 7
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>- and 7
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-hydroperoxide
s of the
sterol
s were obtained by allowing an aliquot of the5
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>-hydroperoxide
s to i
somerize to 7
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>-hydroperoxide
s, which in turn epimerize to 7
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-hydroperoxide
s.The reduction gave the corre
sponding 7
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>- and 7
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-hydroxy derivative
s. The 5
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>-, 7
![](/image<font color=)
s/gifchar
s/alpha.gif" BORDER=0>-, and 7
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-hydroxyderivative
s of
![](/image<font color=)
s/gifchar
s/beta2.gif" BORDER=0 ALIGN="middle">-
sito
sterol, campe
sterol,
stigma
sterol, and bra
ssica
sterol were identified by comparingthin-layer chromatography mobilitie
s,
specific color reaction
s, and ma
ss spectral data with tho
se ofthe corre
sponding hydroxy derivative
s of chole
sterol, which were
synthe
sized in the
same manner.The phyto
sterol
s had the
same behavior to photooxidation a
s chole
sterol and, moreover, the differentphyto
sterol
s photooxidized at about the
same rate. The ma
ss spectra of the trimethyl
silyl ether
s ofthe hydroxy derivative
s of the phyto
sterol
s inve
stigated and of the corre
sponding hydroxy derivative
sof chole
sterol have the
same fragmentation pattern
s and
similar relative ion abundance
s.Keyword
s: Sterol
s; phyto
sterol
s; hydroxy
sterol
s; photooxidation; ga
s chromatography/ma
ssspectrometry; GC/MS; ma
ss spectra; trimethyl
silyl ether