Ecalcidene (1-[(1alpha,3beta,5Z,7E,20S)-1,3-dihydroxy-24-oxo-9,10-secochola-5,7,10(19)-
trien-24-yl]-
piperidine) is a new 1-hydroxyvitamin D analogue. In this report, the thermal degradation,
acid induced degradation and
iodine induced degradation of
ecalcidene were investigated using HPLC-MS, HPLC-NMR and chemical derivatization. In
solution ecalcidene was thermally and reversibly transformed to a pre-
Vitamin D type isomer 1 which subsequently produced the dehydrated pyrocalciferol and isopyrocalciferol type isomers 2 and 3 by cyclization and
dehydration at elevated temperatures. Acidic conditions resulted in the formation of a novel C9-hydroxylated isomer 4 of
ecalcidene, possibly via a tachysterol type intermediate, followed by the
acid facilitated nucleophilic addition of water. In the presence of
iodine, cis/trans isomerization of both
ecalcidene and its pre-
Vitamin D type isomer 1 occurred. The results may shed light on the stability and metabolism of
ecalcidene, provide useful information for its potential
pharmaceutical development, and enrich the knowledge of
Vitamin D chemistry.