ISSN:
0170-2041
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Chemistry and Stereochemistry of Iridoids, VIII. - Oxidation of the Enol-Ether Function of Catalpol Derivatives to the LactoneOxidation of 2′,3′,4′,6,6′,10-hexaacetylcatalpol (1a), 2′,3′,4′,6-tetraacetyl-6′,10-bis(triphenylmethyl)catalpol (1b), and 2′,3′,4′,6′,10-pentaacetyl-6-(acetylvanilloyl)catalpol (1c) by N-bromosuccinimide/dimethyl sulfoxide is described. A mixture of the two possible diastereomeric α-bromolactones 2 is obtained in each case. This mixture can be reduced as crude product in dry tetrahydrofuran by treatment with zinc/acetic acid to yield more than 70% of the halogen-free lactones 3. The mechanism of the reaction is discussed.
Notes:
Die Oxidation von 2′,3′,4′,6,6′,10-Hexaacetylcatalpol (1a), 2′,3′,4′,6-Tetraacetyl-6′,10-bis(triphenylmethyl)catalpol (1b) und 2′,3′,4′,6′,10-Pentaacetyl-6-(acetylvanilloyl)catalpol (1c) mit N-Bromsuccinimid/Dimethylsulfoxid wird beschrieben. Das jeweils entstehende Diastereomerengemisch der zwei möglichen α-Bromlactone 2 läßt sich als Rohprodukt mit Zink/Eisessig in wasserfreiem Tetrahydrofuran zu den halogenfreien Lactonen 3 reduzieren, wobei die Gesamtausbeuten höher als 70% sind. Der Reaktionsmechanismus wird diskutiert.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.198719870312
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