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Structure of Two Oxidation Products of β‐Lumicolchicine: A Remarkable Reaction with Active Manganese Dioxide
Author(s) -
Buddrus Joachim,
Defoin Albert,
Krüger Carl,
Tsay YiHung,
Kuhn Hans Jochen
Publication year - 1989
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.198919890271
Subject(s) - chemistry , cyclobutene , epoxide , oxazoline , adduct , ring (chemistry) , double bond , intermolecular force , manganese , permanganate , medicinal chemistry , stereochemistry , polymer chemistry , molecule , organic chemistry , catalysis
Two unusual reaction types of MnO 2 and of m ‐chloroperbenzoic acid with the tetrasubstituted CC bond of β‐lumicolchicine ( 1 ‐β) are presented. Active MnO 2 oxidizes the 7a,10b cyclobutene double bond by adding a hydroxy group to the position 10b while the acetamido side chain is used to close a 2‐oxazoline ring in position 7a ( 2 ). m ‐Chloroperoxybenzoic acid splits the cyclobutene ring of 1 ‐β and forms a ketonic 1:1 adduct ( 3 ) instead of an epoxide. X‐ray structure analysis of 2 reveals intermolecular interaction between the hydroxy groups and the nitrogen atoms. 2D‐INADEQUATE 13 C‐NMR spectroscopy establishes structure 2 in solution, proves the structure of 3 , and allows also to assign the 13 C‐NMR signals of the tetracyclic skeleton of the stereoisomeric lumicolchicines 1 ‐β and 1 ‐γ. Furthermore, 13 C, 13 C coupling constants were determined for 2 and 3 .