Moxidectin O-TBS is an intermediate used in the synthesis of (I2,3S)-23-des(methoxyimino)-23-[(methylsulfanyl)methoxy]moxidectin (D292840), which is an impurity of moxidectin (M744800), a macrocyclic lactone and semisynthetic derivative of nemadectin. Moxidectin is a parasiticide used for the prevention and control of heartworm and intestinal worms. Moxidectin is found in veterinary medicine used to treat animals such as dogs, cats, horses, cattle and sheep.