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A new synthesis of [26,28‐ 2 H 6 ]brassinolide and [26,28‐ 2 H 6 ]castasterone via an unusual methyl migration
Author(s) -
Kolbe A.,
Porzel A.,
Schmidt J.,
Adam G.
Publication year - 2003
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.662
Subject(s) - brassinolide , chemistry , ethylenedioxy , epoxide , stereochemistry , deuterium , nitrile , medicinal chemistry , organic chemistry , alkyl , botany , plant growth , physics , quantum mechanics , biology , catalysis
Abstract Deuterium‐labelled brassinosteroids, namely [26,28‐ 2 H 6 ]castasterone, 8 , and [26,28‐ 2 H 6 ]brassinolide, 9 , were synthesized starting from 6,6‐ ethylenedioxy‐20‐formyl‐2α,3α‐isopropylidenedioxy‐5α‐pregnane, 1 , and 3‐[ 2 H 3 ]methyl‐but‐1‐yne‐[4,4,4‐ 2 H 3 ], 11 . Upon alkylating cleavage of the epoxide 6 with trimethylaluminium‐n‐butyllithium an unusual migration of a neighbouring [ 2 H 3 ]methyl group takes place to afford deuteriation at positions 26 and 28. Copyright © 2002 John Wiley & Sons, Ltd.