Lee, D.-U. and Iwasa, K. and Kamigauchi, M. and Takao, N. and Wiegrebe, Wolfgang (1991) Degradation of some Phthalideisoquinolines with Ethyl Chloroformate-Stereochemical Aspects. Chemical & Pharmaceutical Bulletin 39 (8), pp. 1944-1948.
Treatment of phthalideisoquinolines such as α- (1) and β-narcotine (2) as well as ß-(3) and α-hydrastine (4) with
ethyl chloroformate (ECF) at room temperature afforded, via the chloro-carbamates, the corresponding diastereomeric
carbinols with high stereoselectivity. Instrumental analyses of each diastereomeric pair indicate that the major isomers
derived from α- and β-narcotine as well as from α - and β -hydrastine are enantiomers of each other. The absolute
configuration of the major carbinol 6a from α -narcotine (1) was determined by X-ray analysis. The probable difference
between the reaction course of α - and β-narcotine is discussed. On the other hand, treatment of α-narcotine with ECF
under reflux furnished Z-(8) and E-(9) enol lactones, while only the Z-isomer 12 could be isolated from the degradation
of β-hydrastine (3) even at room temperature.
|Institutions:||Chemistry and Pharmacy > Institute of Pharmacy > Retired Professors > Prof. Wiegrebe|
|Keywords:||α-narcotine; β-narcotine; α-hydrastine; β-hydrastine; ethyl chloroformate; diastereoselectivity; enantiomer; diastereomeric carbinol; enol lactone; X-ray analysis; absolute configuration|
|Subjects:||500 Science > 540 Chemistry & allied sciences|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||08 Jul 2010 05:08|
|Last Modified:||20 Jul 2011 22:32|