EXPERIMENTAL
General methods: NMR spectra were recorded on a BRUKER ARX 500 spectrometer in CDCl3 and CgD6 at 500.14 MHz for ‘H and 125.77 MHz for 13C at 300 K. Chemical shifts were referenced to
solvent peaks: 6~ 7.24 and 6~ 77.0 for CDCl3. Optical rotations were determined with a JASCO DIP- 1000 digital polarimeter. El mass spectra were measured with a JEOL JMS-SX102A mass spectrometer.
IR spectra were recorded on a JASCO IR-700 infrared spectrometer. Aotifouling assay: Adult barnacles, &zlunus umphitrite, attached to bamboo poles were procured from oyster farms in Lake Hamana, Shizuoka, and maintained in an aquarium at 25 “C by feeding on Artemia s&u nauplii. Broods released I-II stage nauplii upon immersion in seawater after being dried for 2 days.
Nauplii thus obtained were cultured in 80 % filtered seawater at 25 “C by feeding with the diatom Chaetoceros gradis. The seawater and diet were renewed everyday. Larvae reached the cyprid stage in 5 days. The cyprids were stored at 5 “C until used.