| 摘要 |
The present invention provides a novel P2X3 and/or P2X2/3 receptor antagonist. A compound represented by the formula (I); wherein Ra, Rb and Rc are, (a) Ra and Rb are taken together ═Z; and Rc is a group represented by R1c; or (b) Rb and Rc are taken together to form a bond; and Ra is a group represented by —Y—R1a; R1a and R1c are each independently hydrogen, substituted or unsubstituted alkyl, etc.; R2 and R3 are each independently substituted or unsubstituted aryl, etc.; R4a and R4b are each independently hydrogen, substituted or unsubstituted alkyl, etc.; X is —N(R5)—, etc.; R5 is hydrogen, substituted or unsubstituted lower alkyl, etc.; —Y— is —O—, etc.; ═Z is ═O, etc.; and n is an integer of 0 to 4. |
