Derquantel

CAS 187865-22-1

Derquantel (CAS 187865-22-1) illustrates how molecular structure determines chemical role. Derquantel is a semisynthetic anthelmintic belonging to the spiroindole class and was developed for control of gastrointestinal nematodes in livestock. It acts as an antagonist at nematode nicotinic acetylcholine receptors, disrupting neuromuscular signaling and producing flaccid paralysis of susceptible worms. Derquantel is especially known in veterinary medicine through combination with the macrocyclic lactone abamectin, marketed for sheep in some jurisdictions. Combining agents with different mechanisms broadens parasite control and was developed in the context of widespread resistance to older anthelmintic classes. Chemically, derquantel's densely fused spirocyclic framework distinguishes it sharply from simpler benzimidazole or imidazothiazole dewormers. Its story therefore connects natural-product-inspired molecular architecture, parasite neurobiology, and the practical challenge of maintaining effective livestock parasite control.