Collect. Czech. Chem. Commun. 2004, 69, 2068-2080

Synthesis and Conformational Analysis of New 17-Alkyl Derivatives of Lupanine and Their Perchlorate Salts

Beata Jasiewicz, Władysław Boczoń* and Joanna Kurek

Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland


New 17-alkyl derivatives of lupanine and their perchlorate salts have been synthesised. Substituents at C-17 are introduced by treatment of C(17)=N(16) immonium perchlorate 2 with alkylmagnesium compounds. NMR spectra of the new compounds have been taken to study the chemical shift changes caused by the introduced alkyl substituents, ethyl and butyl. In 17-alkyl derivatives (17-ethyl- (3) and 17-butyllupanine (4)) the substituent is equatorially oriented. All the lupanine derivatives analysed have the same structure, i.e. ring C in a boat conformation. The reaction of 17-butyllupanine (4) and 17-cyanolupanine (5) with methyllithium has led to 17-butyl-2-methyl-2,3-didehydrosparteine (6), 17-butyl-2-methylsparteine (7) and 17-cyano-2-methyl-2,3-didehydrosparteine (8).

Keywords: Bisquinolizidine alkaloids; Lupanine derivatives; Grignard reaction; Alkyl substituents; NMR spectroscopy; IR spectroscopy; Tertiary amines.

References: 21 live references.