Three New Pteridines, Hirudinoidines A -C, from Hirudo nipponica WHITMAN

Three new pteridines, hirudinoidines A – C (1–3, resp.), with novel structural features were isolated from Hirudo nipponicaWhitman, and their structures were elucidated on the basis of extensive spectroscopic analyses and by comparison of their spectral data with those of related metabolites. The configuration of 1 was unequivocally confirmed by single-crystal X-ray diffraction (Fig. 2).