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Synthesis and determination of configuration of natural 25-hydroxyvitamin D(3) 26,23-lactone
T Eguchi1, S Takatsuto, M Ishiguro
1Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152 Japan.
Abstract:
The four stereoisomers of 25-hydroxyvitamin D(3) 26,23-lactone were synthesized by a stereoselective lactonization method. Natural 25-hydroxyvitamin D(3) 26,23-lactone was produced from 25-hydroxy-[3alpha-(3)H]vitamin D(3) by in vitro incubation of kidney homogenate prepared from vitamin D-supplemented chickens or was isolated from the serum of rats given 1,25-dihydroxyvitamin D(3) and 25-hydroxy-[3alpha-(3)H]vitamin D(3). The four synthetic isomers and the naturally produced 25-hydroxyvitamin D(3) 26,23-lactone were subjected to high-performance liquid chromatography in a system capable of separating the four isomers. The natural lactone comigrated with synthetic (23S,25R)-25-hydroxyvitamin D(3) 26,23-lactone, establishing it as the natural vitamin D(3) metabolite.
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