Isoxazole derivatives have been shown to possess anti-parasitic activi
ty. In the present study, 3-substituted 5-methylthio-isoxazoles were s
ynthesized and tested for anthelmintic activity, along with some other
isoxazoles which have been reported but not tested earlier. Nine comp
ounds (2a, 2b, 2e, 2g, 2u 3a, 3b, 3e and 3f) showed activity against b
oth A. ceylanicum and N. dubius in vitro. Twelve compounds (2a, 2b, 2d
, 2e, 2f, 2h, 2l, 2n, 2o, 2u, 3d and 3e) showed activity against N. du
bius in vivo, a parasite of veterinary importance.