Disclosed are compounds represented by formula (I) which have triglyceride biosynthesis inhibitory activity in the liver and inhibitory activity against the secretion of apolipoprotein B-containing lipoprotein from the liver and particularly have excellent inhibitory activity against the secretion of apolipoprotein B-containing lipoprotein, are free from side effect of accumulation of lipids in the liver, and are useful for the treatment and prevention of hyperlipidemia and arteriosclerotic diseases. In formula (I), R¹ and R² represent alkyl, alkoxy, cycloalkyl, phenyl, alkenyl, alkynyl, or a five- or six-membered saturated or unsaturated heterocyclic ring, or R¹ and R², together with a nitrogen atom to which R¹ and R² are attached, may form a ring; R³ and R⁴ represent a hydrogen atom, alkyl, a halogen atom, hydroxyl, nitrile, alkoxycarbonyl, alkoxy, or carboxyl; or R² and R³ may be attached to each other to form —(CH₂)_m—, —NCH—, —CHN—, or —(C_1-6 alkyl)CN—; A, D, E, and G each represent a carbon atom, or any one of A, D, E, and G represents a nitrogen atom with the other three each representing a carbon atom; Q represents a nitrogen atom or a carbon atom; Y represents a group represented by formula (II) wherein X represents a hydrogen atom, group —C(O)N(R⁵)R⁶ or group —C(O)OR⁷, R⁸ is absent or represents a bond, an oxygen atom, a sulfur atom, —SO₂—, —SO—, —CH₂—CH₂—, or —CHCH—, and R⁹ and R¹⁰ represent a hydrogen atom, alkyl, alkoxy, a halogen atom, or hydroxyl; and Z represents —(CH₂)_n—, —O—(CH₂)_i—, or —C(O)NH—(CH₂)_i— ##STR1##