4a-Substituted avermectin compounds, their production and antiparasitic use, and compositions containing them.

摘要

Novel avermectin compounds in which the 4-methyl group is substituted have the formula <CHEM> where X is -CH2-CH2, -CH2-@@-, -CH=CH-, or -CH2@-; R1 is methyl, ethyl, isopropyl or sec-butyl; R2 is hydrogen, methyl, acetyl, phenoxyacetyl or tert-butyl dimethylsilyl; R3 is hydrogen, hydroxy, acetoxy, alpha -L-oleandrosyloxy, 4 min -acetyl- alpha -L-oleandrosyloxy, 4 min -( alpha -L-oleandrosyl)- alpha -L-oleandrosyloxy, 4 sec -acetyl min -4-( alpha -L-oleandrosyl)- alpha -L-oleandrosyloxy, or 4 sec -(phenoxyacetyl)-4 min -( alpha -L-oleandrosyl)- alpha -L-oleandrosyloxy; and R4 is hydrogen, acetyl, benzoyl, pyridinylcarbonyl, pyrrolylcarbonyl, -CO(CH2)nCOOH, or -CO(CH2)nCOOM, where n is 2, 3 or 4 and M is an alkali metal or an ammonium or diloweralkyl ammonium cation; provided that R4 is pyrrolylcarbonyl only when R1 is isopropyl or sec-butyl. The compounds in which R4 is hydrogen are prepared by oxidation of the 4-methyl group and the other prepared by a substitution process selective for primary alcohols. The compounds have utility as antiparasitic agents and compositions for that use are also disclosed.