Condensed heterocyclic compounds, their production and use

摘要

Novel compound represented by the formula: wherein ring A, ring B and ring C each stands for an optionally substituted benzene ring; X stands for -NR-wherein R stands for hydrogen atom or an optionally substituted hydrocarbon group, -O- or -S-; Y stands for -(CH2)n- wherein n denotes 1 or 2 or -NH-; and R stands for a hydrogen atom or an optionally substituted hydrocarbon group, provided that when ring C is unsubstituted or substituted only at para-position, ring B is substituted at least at ortho-position or a salt thereof which have an excellent acyl-CoA: cholesterol acyltransferase inhibiting action and cholesterol-lowering activity, their production and medicinal use.