Milbemycins alpha 11, alpha 12, alpha 13, alpha 14 and alpha 15: a new family of milbemycins from Streptomyces hygroscopicus subsp. aureolacrimosus. Taxonomy, fermentation, isolation, structure elucidation and biological properties

Abstract

Streptomyces hygroscopicus subsp. aureolacrimosus SANK 60286 produces a new family of milbemycins, named milbemycins alpha 11, alpha 12 [corrected], alpha 13, alpha 14 and alpha 15, together with other milbemycins. Their structures are 3-methyl-2-butenoyloxy and 3-methylbutyroyloxy derivatives at C-4a of milbemycins A3 and A4, or 3-methyl-2-pentenoyloxy derivative at C-4a of milbemycin A3, respectively. Milbemycin alpha 14, 3-methyl-2-butenoyloxy derivative, especially possesses a potent acaricidal activity.