Substituted acetamide derivatives for treatment of hypocholesterolaemia, hyperlipaemia and arteriosclerosis

There are provided substituted acetamide derivatives represented by general formula (I): wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, n and Z are defined in the specification. The substituted acetamide derivatives strongly inhibit acylcoenzyme A cholesterol acyltransferase (ACAT) and are expected to be effective for the treatment and prevention of hypercholesterolemia, hyperlipemia and arteriosclerosis.