Ochtodene derivatives from the red alga Carpopeltis crispata.

Red algae are well known as a source of halogenated monoterpenes such as derivatives of ochtodene. From Carpopeltis crispata, we have isolated four new ochtodene derivatives: dibromodichloro-, dibromochloro-, and bromodichlorocyclomonoterpenes. The structures of these monoterpenes were confirmed by NMR and mass spectroscopy and compared with spectral data in the literature.