Use of cyclic depsipeptide having 12 ring atoms for combating endoparasites, new cyclic depsipeptide having 12 ring atoms and production thereof

PURPOSE: To provide a novel cyclic depsipeptide having 12 ring atoms obtained by the cyclizing reaction of a closed tetradepsipeptide in the presence of a diluent and a coupling agent and useful as a medicine and a veterinary medicine for combating endoparasites. CONSTITUTION: This novel cyclic depsipeptide having 12 ring atoms useful as a medicine and a veterinary medicine for combating endoparasites is represented by formula I [wherein R 1 and R 4 are each H, (substd.)alkyl, cycloalkyl, aryl, heteroaryl or the like; and R 2 , R 3 , R 5 and R 6 are each H, 1-8C alkyl, halogenoalkyl, hydroxyalkyl, alkoxyalkyl, mercaptoalkyl, alkylthioalkyl, aminoalkyl, (substd.)aryl, heteroaryl or the like], an optical isomer thereof and a racemate thereof. The cyclic depsipeptide is obtained by cyclizing a closed tetradepsipeptide represented by formula II in the presence of a diluent and a coupling agent. COPYRIGHT: (C)1995,JPO