Synthese der macrocyclischen Spermidin‐Alkaloide Oncinotin, Neooncinotin, Isooncinotin und Pseudooncinotin in racemischer Form. 159. Mitteilung über Alkaloide

Abstract

Synthesis of the Macrocyclic Spermidine Alkaloids Oncinotine, Neooncinotine, Isooncinotine and Pseudooncinotine in Racemic Forms . The four isomeric spermidine alkaloids ( Scheme 1 ) mentioned in the title were synthesized as follows: Reaction of the piperidine derivative 5 and the bromide 6 led to the intermediate 13 which was converted to (±)‐oncinotine (±‐ 1 ) and (±)‐pseudooncinotine (±‐ 4 ) ( Scheme 3 ). The analogous reaction of 5 and the isomeric bromid 7 gave the intermediate 22 from which (±)‐neooncinotine (±‐ 2 ) and (±)‐isooncinotine (±‐ 3 ) were synthesized ( Scheme 4 ). The overall yields were found to be between 22 (±‐ 1 ) and 54% (±‐ 3 ).