TY - JOUR
T1 - Absolute configuration assignment of stigmasterol oxiranes
AU - Fuentes-Figueroa, Miguel
AU - Joseph-Nathan, Pedro
AU - Burgueño-Tapia, Eleuterio
N1 - Publisher Copyright:
© 2021 Wiley Periodicals LLC.
PY - 2022/2
Y1 - 2022/2
N2 - Diastereoisomeric stigmasterol oxiranes 4, 5, 8, and 9 are known phytosterol oxidation products (POPs) that have been evaluated for their cytotoxicity, although the results are of limited significance since, in most cases, they were evaluated as mixtures. Consequently, to establish biological activity hierarchy of these oxides, it is critical to evaluate individual pure POPs. Therefore, we now describe the obtention of individual molecules and their absolute configuration (AC) determination. The two acetylated C-5−C-6 oxiranes 6 and 7; the two acetylated C-22−C-23 oxides 10 and 11, obtained by means of Δ5 double bond protection-deprotection; and the four C-5−C-6, C-22−C-23 diepoxystigmasteryl acetates 19–22 were now individually gained and their AC determined by vibrational circular dichroism. Vibrational modes associated with the C-5−C-6 and the C-22−C-23 bonds were identified in dioxiranes 19–22 and used to assign the AC of monoepoxides 6, 7, 10, and 11. The AC of biological active non-acetylated molecules follows immediately. Due to the scarce spectroscopic information available for these POPs, the 1H and 13C NMR chemical shifts of 3–22 were assigned using 1D- and 2D-NMR experiments.
AB - Diastereoisomeric stigmasterol oxiranes 4, 5, 8, and 9 are known phytosterol oxidation products (POPs) that have been evaluated for their cytotoxicity, although the results are of limited significance since, in most cases, they were evaluated as mixtures. Consequently, to establish biological activity hierarchy of these oxides, it is critical to evaluate individual pure POPs. Therefore, we now describe the obtention of individual molecules and their absolute configuration (AC) determination. The two acetylated C-5−C-6 oxiranes 6 and 7; the two acetylated C-22−C-23 oxides 10 and 11, obtained by means of Δ5 double bond protection-deprotection; and the four C-5−C-6, C-22−C-23 diepoxystigmasteryl acetates 19–22 were now individually gained and their AC determined by vibrational circular dichroism. Vibrational modes associated with the C-5−C-6 and the C-22−C-23 bonds were identified in dioxiranes 19–22 and used to assign the AC of monoepoxides 6, 7, 10, and 11. The AC of biological active non-acetylated molecules follows immediately. Due to the scarce spectroscopic information available for these POPs, the 1H and 13C NMR chemical shifts of 3–22 were assigned using 1D- and 2D-NMR experiments.
UR - http://www.scopus.com/inward/record.url?scp=85119139243&partnerID=8YFLogxK
U2 - 10.1002/chir.23390
DO - 10.1002/chir.23390
M3 - Artículo
C2 - 34788903
AN - SCOPUS:85119139243
SN - 0899-0042
VL - 34
SP - 396
EP - 420
JO - Chirality
JF - Chirality
IS - 2
ER -