Quinazoline derivative

摘要

This invention provides a compound or its pharmaceutically-acceptable salt of formula (I) wherein R1 represents a lower alkyl group et al; R2 and R3 are same and different and represents hydrogen atm et al; R4 represents the substituent of the formula (II) et al; X1 represents NH, O or S; Y represents N or C; Ar is a divalent substituent derived from aryl et al, by removing two hydrogen atoms therefrom; the ring A represents a 5- or 6-membered heteroaryl group; this compounds has a histamine-H3 receptor antagonistic effect or a histamine-H3 receptor inverse-agonistic effect and is useful for preventive or remedy of metabolic system diseases, circulatory system diseases or nervous system diseases.