Premium
Ein selektiver Abbau der Exomethylengruppe von Vitamin D. – Ein einfacher Zugang zu 10‐Oxo‐19‐norcholecalciferol und 10‐Oxo‐19‐norergocalciferol
Author(s) -
Reischl Wolfgang
Publication year - 1993
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199319930196
Subject(s) - chemistry , isomerization , double bond , stereochemistry , nitrile , vitamin , medicinal chemistry , polymer chemistry , organic chemistry , catalysis , biochemistry
A Selective Degradation of the Exomethylene Group of Vitamin D. – A Simple Entry to 10‐Oxo‐19‐norcholecalciferol and 10‐Oxo‐19‐norergocalciferol Nitrile oxides, generated in situ from nitroalkanes, add exclusively to the exomethylene group of ( Z )‐ and ( E )‐vitamin D 3 acetates ( 1a , 12a ) and D 2 acetates ( 1b , 12b ). The so generated spirocyclic isoxazoline derivatives are transformed through a Mo(CO) 6 ‐induced fragmentation into (5 Z ,7 E )‐ and (5 E ,7 E )‐(3 S )‐3‐acetoxy‐19‐nor‐9,10‐secocholesta‐5,7‐dien‐10‐one ( 20a , 22a ) as well as (5 Z ,7 E ,22 E )‐ and (5 E ,7 E ,22 E )‐(3 S )‐3‐acetoxy‐19‐nor‐9,10‐secoergosta‐5,7,22‐ trien‐10‐one ( 19a , 21a ). The discribed method allows the synthesis of 19‐nor‐10‐oxo vitamin D derivatives without partial isomerisation of the Δ 5 ‐double bond.