Delta-2-Avermectin B1a is a natural, irreversible base degradation product produced by selective hydrolysis of the terminal saccharide Avermectin under acidic conditions in animals and in the environment. Delta-2-Avermectin B1a is formed by rearrangement of the naturally-occurring delta-3-group to the 2-position. Although less active than the parent, Delta-2-Avermectin B1a is nonetheless active at 1 ppm. Avermectins are a family of natural macrocyclic lactones produced by the soil actinomycete Streptomyces avermitilis. There are eight different Avermectin natural product compounds: A1a, A1b, A2a, A2b, B1a, B1b, B2a, and B2b based upon the structure of the individual compounds. The B1 fraction has the most effective antiparasitic activity.
Delta-2-Avermectin B1a is soluble in ethanol, methanol, DMF and DMSO.