Compound having bicyclic pyrimidine structure and pharmaceutical composition comprising the same

The present invention relates to a bicyclic pyrimidine compound of the following formula (I) or a salt thereof. wherein R1 is lower alkyl, cyclic lower alkyl. etc.; R2 is H, lower alkyl, lower alkenyl, etc.; R3 is H, lower alkyl, lower alkenyl, etc.; X is O, S or -N(R4)-; R4 is H or lower, alkyl; or R2 and R4 may combine each other to form cyclic amino; Y is amido, keto, sulfonyl, etc.; R5 is H or lower alkyl; Z is O or S; m and n are 1 or 2. Said compound (I) or a salt thereof have MGAT inhibitory activity, and are useful as an agent for treatment or prophylaxis of adiposity, metabolic syndromes, hyperlipidemia, hyper neutral lipemia, hyper VLDL-mia, hyper fatty acidemia, diabetes mellitus, arteriosclerosis.