Bohemamines from a marine-derived Streptomyces sp.

Investigation of the culture extracts of a marine-derived Streptomyces sp. led to the isolation of three new bohemamine-type pyrrolizidine alkaloids, bohemamine B (1), bohemamine C (2), and 5-chlorobohemamine C (3). The structures were elucidated using NMR methods, and the relative stereochemistry was determined using double-pulsed-field-gradient spin echo (DPFGSE) NOE studies.