(6R,25)-5-O-Demethyl-28-deoxy-6,28-epoxy-25-(1-methylethyl)milbemycin B 77855-81-3 Antibiotic B 41D B 41D BRN 4282549 Milbemycin B, 5-O-demethyl-28-deoxy-6,28-epoxy-25-(1-methylethyl)-, (6R,25R)- Milbemycin D