Synthesis and antialgal activity of dihydrophenanthrenes and phenanthrenesII: Mimics of naturally occurring compounds in Juncus effusus

9,10-Dihydrophenanthrenes and phenanthrenes, mimics of natural compounds wi th strong antialgal activity, have been synthesized through cross-coupling by zerovalent Ni of 1-(2-iodo-5-methoxy)-phenylethanol or 2-iodo-5 methoxya cetophenone with iodoxylenes. The synthetic compounds had a hydroxyl or a m ethoxyl group at C-2 and two methyls in the C ring. Assays on the green alg a Selenastrum capricornutum showed that all the compounds, except 2-methoxy -5,7-dimethylphenanthrene, caused strong inhibition of algal growth at 10(- 4) M. 2-Hydroxy-7.8-dimethyl-9,10-dihydrophenanthrene and 2-methoxy-5,6-dim ethylphenanthrene fully inhibited growth at 10(-5) M.