Tricyclic dihydrobenzofuran derivatives, process for the preparation thereof and agents

摘要

A compound represented by the formula:wherein Ring A is a non-aromatic 5- to 7-membered nitrogen-containing heterocyclic ring which may be further substituted, Ring B is benzene ring which is further substituted, Ring C is a dihydrofuran-ring which may be further substituted and R is hydrogen atom or an acyl group or a salt thereof has an excellent lipid peroxidation inhibitory activity and is useful as a lipid peroxidation inhibitor.