Chemistry of the Coccoidea. II. Condensed polycyclic pigments from two Australian pseudococcids (Hemiptera)

Abstract

The mealy bugs Nipaecoccus aurilanatus (Maskell) and Pseudococcus albizziae (Maskell) have been found to contain the novel hypericin monocarboxylic acid (8). N. aurilanatus also contains hypericin(7) and the anthraquinones (1), (2), (3) and (4) while P. albizziae contains the protohypericins (13) and (14), skyrin (6) and the anthraquinones (1), (2) and (3). A reinvestigation of the oxidation ofemodin bianthrone (17) has provided useful syntheses of skyrin (6) and protohypericin (13), and provided an unambiguous synthesis of the hypericin monocarboxylic acid (8). The substance 'isohypericin' (21) could not be obtained by the literature procedure, reaction affording protohypericin (13) as the only isolable product.