Defensive substances of Coccinella transversoguttata and Hippodamia caseyi, ladybugs indigenous to western Canada

Abstract

The defensive substances of two species of ladybug indigenous to western Canada have been isolated. The known compounds precoccinelline (1) and coccinelline (2) are present in Coccinella transversoguttata, and hippodamine (3) and convergine (4) in Hippodamia caseyi. From the latter insect we have also isolated two new alkaloids, a new base, N-oxide pair, which we have named hippocasine and hippocasine oxide. The structure of hippocasine oxide (8) was established by spectroscopic methods and confirmed by X-ray analysis of the hydrochloride (9d and Fig. 1).