Biosynthesis of the indolizidine alkaloid cyclizidine: Incorporation of singly and doubly labelled precursors

Abstract

Incorporation of CH 3 13 C 18 O 2 Na and CD 3 CH 2 13 CO 2 Na into the indolizidine alkaloid cyclizidine 1, produced by Streptomyces species NCIB 11649, shows that the oxygen attached to C-2 is derived intact from acetate and that the cyclopropyl ring is derived from a single intact propionate unit. However, the level and stereochemistry of the incorporation of deuteriated sodium propionate indicates that it undergoes unexpected modification during incorporation into the cyclopropyl ring.