| 摘要 |
Avermectin derivatives are disclosed wherein the 4 sec -hydroxy group is replaced by a substituted alkylthio or acylthio group or an iodo group. These avermectin derivatives can be further derivatized at the 5- and 23-positions as ketoximes or O-substituted ketoximes. The 4 sec -substituted avermectin derivatives are prepared from the 4 sec - and 4 min -trifluoromethanesulfonyl avermectin derivatives with halo- or sulfur-containing nucleophiles. The 4 sec - and 4 min - alpha -and beta -trifluoromethane sulfonates are prepared selectively and converted into 4 sec - or 4 min -alkyl- or acylsulfides, or iodides using the appropriate sulfur-containing or iodine nucleophile. Substituted sulfoxy and sulfonyl substituents at the 4 sec - and 4 min -positions are prepared from oxidation of the corresponding substituted sulfides. The new compounds are potent anti-parasitic agents; in particular, the compounds are anthelmintic, insecticidal and acaricidal agents. |
