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Stereospecific synthesis of Δ 24 ‐sterols labelled on the 26‐ or 27‐methyl group
Author(s) -
Nicotra F.,
Ronchetti F.,
Russo G.
Publication year - 1978
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580140409
Subject(s) - lanosterol , chemistry , stereospecificity , hydrogenolysis , stereochemistry , aldehyde , alcohol , olefin fiber , hydroxymethyl , methyl group , group (periodic table) , organic chemistry , sterol , catalysis , cholesterol , biochemistry
A convenient synthesis of Δ 24 ‐sterols labelled on the 26‐ or 27‐methyl group, exemplified by the synthesis of [26‐ 3 H]‐lanosterol, is described. Oxidation of lanosteryl acetate with SeO 2 gives 3β‐acetoxylanosta‐8, 24‐dien‐26‐al; this is reduced to the corresponding labelled alcohol with KB 3 H 4 and the obtained hydroxymethyl group is reduced to methyl group by hydrogenolysis of its sulfate monoester. 26‐Hydroxylanosterol can be transformed into 27‐hydroxy lanosterol by E→Z olefin inversion, so allowing the synthesis of lanosterol stereospecifically labelled at C‐27. Desmosteryl acetate analogously affords the corresponding 26‐aldehyde, which is easily reduced to the 26‐alcohol. 3 H‐stereospecific synthesis.