For the avermectins and milbemycins related compounds, process for their preparation, preparations for the treatment and prevention of parasitic infections in humans and animals and the method for controlling pests in agriculture and horticulture

摘要

Antiparasitic compounds of formula (I): CHEM The broken line at the 22-23 position representing an optional double bond and either R1 is H or OH and the double bond is absent or the double bond is present and R1 is absent; R2 is optionally substituted phenyl, or a group of formula (II): CHEM wherein X is 0, S or -CH2-, abc and d are 0-2 and a+b+c+d/=5 R3 is H or Me R4 is H, OH or 41-(alpha-L-oleandrosyl)-alpha-L-oleandrosyloxy. The compounds are prepared by fermentation of Streptomyces avermitilis in the presence of an N-alkanoyl cysteamine thioester containing R2.