Synthesis and Nematocidal Activity of Hydroxystilbenes

Abstract

Various (£)-hydroxystilbenes were synthesized from (E)j{Z) mixtures of methoxystilbenes through a new (Z)-(E) isomerization method followed by demethylation. The nematocidal activity appears when methoxystilbenes are demethylated to hydroxystilbenes. For this activity, a hydroxy group at the C-2 or C-3 position is necessary. Thus, 2-hydroxy-, 3-hydroxy-, 2,6-dihydroxy-, 3,4-dihydroxy-, 3,5-dihydroxy-, 2,2’-dihydroxy-, 3,3’-dihydroxy-, 3,4’-dihydroxy-, 2-hydroxy-4-methoxy-, 5-hydroxy-2-methoxy-, 2-hydroxy-6-methoxy-, 6-allyloxy-2-hydroxy-, 3-hydroxy-5-methoxy-, and 5-allyloxy-3-hydroxystilbenes showed rather potent nematocidal activity. The activity of 5-allyloxy-3-hydroxystilbene was the strongest [minimal lethal concentration (MLC) = 30 jjm], The activities of the (E) and (Z) isomers were comparable. The activities were also retained, though they were weaker, in the dihydro derivatives, hydroxybibenzyls. © 1992, The Pharmaceutical Society of Japan. All rights reserved.